Apparatus and method for assigning a common packet channel in a CDMA communication system

ABSTRACT

Disclosed is a method for indicating an end of transmitting data frames in order to enable a UTRAN (UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network) to assign a common packet channel to another user equipment (UE) in a UE for a CDMA mobile communication system. The UE requests assignment of any one of a number of common packet channels assignable in the UTRAN; the UE is assigned a common packet channel by the UTRAN in response to the to request; the UE sequentially transmits the data frames and their associated control frames over the assigned common packet channel; and the UE transmits at least one control frame, in an appointed field of which a given bit pattern appointed with the UTRAN is registered, in order to inform the UTRAN of an end of data transmission upon completing data transmission through the data frames.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a common channelcommunication apparatus and method for a CDMA (Code Division MultipleAccess) communication system, and in particular, to an apparatus andmethod for communicating data over a common packet channel in anasynchronous CDMA communication system.

2. Description of the Related Art

An asynchronous CDMA communication system, such as the UMTS (UniversalMobile Telecommunications System) W-CDMA (Wideband Code DivisionMultiple Access) communication system, uses a random access channel(RACH) and a common packet channel (CPCH) for an uplink (or reverse)common channel.

FIG. 1 is a diagram for explaining how to transmit and receive a trafficsignal over the RACH, which is one of the conventional asynchronousuplink common channels. In FIG. 1, reference numeral 151 indicates asignal transmission procedure of an uplink channel, which can be theRACH. Further, reference numeral 111 indicates an accesspreamble-acquisition indicator channel (AICH), which is a downlink (orforward) channel. The AICH is a channel over which a UTRAN (UMTSTerrestrial Radio Access Network) receives a signal transmitted from theRACH and responds to the received signal. The signal transmitted by theRACH is called an “access preamble” (AP), which is created by randomlyselecting a signature for the RACH.

The RACH selects an access service class (ASC) according to the type oftransmission data, and acquires from the UTRAN the right to use achannel using a RACH sub-channel group and an AP defined in the ASC.

In the application and drawings, τ_(X-Y) indicates a time period betweenvariables X and Y. For example, the time period between a preamble (P)and an acquisition indicator (AI) would be represented as τ_(P-AI).

Referring to FIG. 1, a user equipment (UE; or a mobile station inCDMA-2000 system) transmits an AP 162 of specific length using the RACHand then awaits a response from the UTRAN (or a base station in theCDMA-2000 system). If there is no response from the UTRAN for apredetermined time (τ_(p-p)), the UE increases transmission power by aspecific level as represented by 164 and retransmits the AP at theincreased transmission power. Upon detecting the AP transmitted over theRACH, the UTRAN transmits a signature 122 of the detected AP over thedownlink AICH. After transmitting the AP, the UE determines whether thetransmitted signature is detected from the AICH signal that the UTRANhas transmitted in response to the AP. In this case, if the signatureused for the AP transmitted over the RACH is detected, the UE determinesthat the UTRAN has detected the AP, and transmits a message over theuplink access channel.

Otherwise, upon failure to detect the transmitted signature from theAICH signal that the UTRAN has transmitted within a set time τ_(p-p)after transmission of the AP 162, the UE judges that the UTRAN hasfailed to detect the preamble, and retransmits the AP after a lapse of apreset time τ_(p-p). As represented by reference numeral 164, the AP isretransmitted at transmission power increased by ΔP (dB) from thetransmission power at which the AP was previously transmitted. Thesignature used to create the AP is randomly selected from the signaturesdefined in the ASC selected by the UE. Upon failure to receive the AICHsignal using the transmitted signature from the UTRAN after transmissionof the AP, the UE changes, after a lapse of a set time, the transmissionpower and signature of the AP and repeatedly performs the aboveoperation. In the process of transmitting the AP and receiving the AICHsignal, if the signature transmitted by the UE itself is received, theUE spreads, after a lapse of a preset time τ_(AP) _(—) _(AI-MSG), a RACHmessage 170 with a scrambling code for the signature, and transmits thespread RACH message using a predetermined channelization code at atransmission power level corresponding to the preamble to which theUTRAN has responded with the AICH signal (i.e., at initial power for anuplink common channel message).

As described above, by transmitting the AP using the RACH, it ispossible for the UTRAN to efficiently detect the AP and to readily setthe initial power of an uplink common channel message. However, sincethe RACH is not power controlled, it is difficult to transmit packetdata, which has a long transmission time because the UE has a high datarate or has a large amount of transmission data. In addition, since thechannel is allocated through one AP_AICH (Access Preamble-AcquisitionIndicator Channel), the UEs that have transmitted the AP using the samesignature will use the same channel. In this case, the data transmittedby the different UEs collide with one another, so that the UTRAN cannotreceive the data.

To solve this problem, a method for suppressing a collision between theUEs while power controlling the uplink common channel has been proposedfor the W-CDMA system. This method is applied to a common packet channel(CPCH). The CPCH enables power control of the uplink common channel, andshows a higher reliability as compared with the RACH in allocating thechannel to different UEs. Thus, the CPCH enables the UE to transmit adata channel of a high rate for a predetermined time (from several tensto several hundreds of ms). Further, the CPCH enables the UE to rapidlytransmit an uplink transmission message, which is smaller in size than aspecific value, to the UTRAN without using a dedicated channel.

In order to establish the dedicated channel, many related controlmessages are exchanged between the UE and the UTRAN, and a long time isrequired in transmitting and receiving the control messages. Therefore,exchanging many control messages during the transmission of data of acomparatively small size (several tens to several hundreds of ms)creates a situation where valuable channel resources are allocated tocontrol messages rather than data. The control messages are referred toas overhead. Thus, it is more effective to use the CPCH, whentransmitting data of a small size.

However, since several UEs transmit preambles using several signaturesin order to acquire the right to use the CPCH, there may occur acollision between the CPCH signals from the UEs. To avoid thisphenomenon, a method is needed for allocating to the UEs the right touse the CPCH.

The asynchronous mobile communication system uses a downlink scramblingcode to distinguish the UTRANs, and uses an uplink scrambling code todistinguish the UEs. Further, the channels transmitted from the UTRANare distinguished using an orthogonal variable spreading factor (OVSF)code, and the channels transmitted by the UE are also distinguishedusing the OVSF code.

Therefore, the information required by the UE to use the CPCH, includesa scrambling code used for a message part of the uplink CPCH channel, anOVSF code used for the message part (UL_DPCCH) of the uplink CPCH, anOVSF code used for a data part (UL_DPDCH) of the uplink CPCH, a maximumdata rate of the uplink CPCH, and a channelization code for a downlinkdedicated channel (DL_DPCCH) used for power control of the CPCH. Theabove information is typically required when establishing a dedicatedchannel between the UTRAN and the UE. Further, the above information(overhead) is transmitted to the UE through transmission of signalingsignals before establishment of the dedicated channel. However, sincethe CPCH is a common channel rather than a dedicated channel, the aboveinformation is conventionally represented by a combination of thesignatures used in the AP and the CPCH sub-channels to which thesub-channel concept used in the RACH is introduced, in order to allocatethe information to the UE.

FIG. 2 shows a signal transmission procedure of the downlink and uplinkchannel signals according to the prior art. In FIG. 2, in addition tothe method used for the RACH for transmitting the AP, a collisiondetection preamble (CD_P) 217 is used to prevent a collision betweenCPCH signals from the different UEs.

In FIG. 2, reference numeral 211 indicates an operating procedure of anuplink channel performed when the UE requests allocation of the CPCH,and reference numeral 201 indicates an operating procedure of the UTRANto allocate the CPCH to the UE. In FIG. 2, the UE transmits an AP 213.For a signature constituting the AP 213, it is possible to use aselected one of the signatures used in the RACH or to use the samesignature, and the signature can be distinguished using the differentscrambling codes. The signature constituting the AP is selected by theUE based on the above-stated information, as opposed to the method wherethe RACH randomly selects the signature. That is, to each signature aremapped an OVSF code to be used for the UL_DPCCH, an OVSF code to be usedfor the UL_DPDCH, an OVSF code to be used for the UL_Scrambling code andDL_DPCCH, the maximum frame number, and a data rate. Therefore, in theUE, selecting one signature is equivalent to selecting four kinds of theinformation mapped to the corresponding signature. In addition, the UEexamines a status of the CPCH channel which can be presently used in theUTRAN to which the UE belongs, through a CPCH status indicator channel(CSICH) transmitted using an ending part of the AP_AICH beforetransmitting the AP. Thereafter, the UE transmits the AP over the CSICHafter selecting the signatures for the channel to be used out of theCPCHs which can be presently used. The AP 213 is transmitted to theUTRAN at initial transmission power set by the UE. In FIG. 2, if thereis no response from the UTRAN within a time (τ_(p-p)) 212, the LEretransmits the AP represented by AP 215, the higher power leveltransmission. The number of retransmissions of the AP and the waitingtimes are set before a process for acquiring the CPCH channel isstarted, and the LE stops the CPCH channel acquisition process when theretransmission number exceeds a set value.

Upon receipt of the AP 215, the UTRAN compares the received AP with theAPs received from other UEs. Upon selecting the AP 215, the UTRANtransmits AP_AICH 203 as ACK after a lapse of a time (τ_(p-AI)) 202.There are several criteria on which the UTRAN bases its comparison ofthe received APs to select the AP 215. For example, the criteria maycorrespond to a case where the CPCH, for which the UE has requested theUTRAN through the AP, is available, or a case where the receiving powerof the AP received by the UTRAN satisfies the minimum receiving powerrequested by the UTRAN. The AP_AICH 203 includes a value of thesignature constituting the AP 215 selected by the UTRAN. If thesignature transmitted by the UE itself is included in the AP_AICH 203received after transmitting the AP 215, the UE transmits a collisiondetection preamble (CD_P) 217 after a lapse of a time (τ_(p-CD) _(—)_(p)) 214, a time beginning at the time when AP 215 was originallytransmitted. A reason for transmitting the CD_P 217 is to prevent acollision between transmission channels from the various UEs. That is,many UEs belonging to the UTRAN may request the right to use the sameCPCH by simultaneously transmitting the same AP to the UTRAN, and as aresult, the UEs receiving the same AP_AICH may try to use the same CPCH,thereby causing a collision. Each of the UEs which have simultaneouslytransmitted the same AP, selects the signature to be used for the CD_Pand transmits the CD_P. Upon receipt of the CD_Ps, the UTRAN can selectone of the received CD_Ps and respond to the selected CD_P. For example,a criterion for selecting the CD_P can be a receiving power level of theCD_P received from the UTRAN. For the signature constituting the CD_P217, one of the signatures for the AP can be used, and it can beselected in the same manner as in the RACH. That is, it is possible torandomly select one of the signatures used for the CD_P and transmit theselected signature. Alternatively, only one signature can be used forthe CD_P. When there is only one signature used for the CD_P, the UEselects a randomized time point in a specific time period to transmitthe CD_P at the selected time point.

Upon receipt of the CD_P 217, the UTRAN compares the received CD_P withthe CD_Ps received from other UEs. Upon selecting the CD_P 217, theUTRAN transmits a collision detection indicator channel (CD_ICH) 205 tothe UEs after a lapse of a time (τ_(CD) _(—) _(p-CD) _(—) _(I)) 206.Upon receipt of the CD_ICH 205 transmitted from the UTRAN, the UEs checkwhether a value of the signature used for the CD_P transmitted to theUTRAN is included in the CD_ICH 205, and the UE, for which the signatureused for the CD_P is included in the CD_ICH 205, transmits a powercontrol preamble (PC_P) 219 after a lapse of a time (τ_(CD) _(—) _(p-PC)_(—) _(p)) 216. The PC_P 219 uses an uplink scrambling code determinedwhile the UE determines a signature to be used for the AP, and the samechannelization code (OVSF) as a control part (UL_DPCCH) 221 duringtransmission of the CPCH. The PC_P 219 is comprised of pilot bits, powercontrol command bits, and feedback information bits. The PC_P 219 has alength of 0 or 8 slots. The slot is a basic transmission unit used whenthe UMTS system transmits over a physical channel, and has a length of2560 chips when the UMTS system uses a chip rate of 3.84 Mcps (chips persecond). When the length of the PC_P 219 is 0 slots, the present radioenvironment between the UTRAN and the UE is good, so that the CPCHmessage part can be transmitted at the transmission power at which theCD_P was transmitted, without separate power control. When the PC_P 219has a length of 8 slots, it is necessary to control transmission powerof the CPCH message part.

The AP 215 and the CD_P 217 may use the scrambling codes which have thesame initial value but have different start points. For example, the APcan use 0^(th) to 4095^(th) scrambling codes of length 4096, and theCD_P can use 4096^(th) to 8191^(st) scrambling codes of length 4096. TheAP and CD_P can use the same part of the scrambling code having the sameinitial value, and such a method is available when the W-CDMA systemseparates the signatures used for the uplink common channel into thesignatures for the RACH and the signatures for the CPCH. For thescrambling code, the PC_P 219 uses the 0^(th) to 21429^(th) values ofthe scrambling code having the same initial value as the scrambling codeused for AP 215 and CD_P 217. Alternatively, for the scrambling code forthe PC_P 219, a different scrambling code can also be used which ismapped one-to-one with the scrambling code used for AP 215 and CD_P 217.

Reference numerals 207 and 209 denote a pilot field and a power controlcommand field of a dedicated physical control channel (DL_DPCCH) out ofa downlink dedicated physical channels (DL_DPCHs), respectively. TheDL_DPCCH can use either a primary downlink scrambling code fordistinguishing the UTRANs or a secondary scrambling code for expandingthe capacity of the UTRAN. For a channelization code OVSF to be used forthe DL_DPCCH, a channelization code that is determined when the UEselects the signature for the AP is used. The DL_DPCCH is used when theUTRAN performs power control on the PC_P or CPCH message transmittedfrom the UE. The UTRAN measures receiving power of a pilot field of thePC_P 219 upon receipt of the PC_P 219, and controls transmission powerof the uplink transmission channel transmitted by the UE, using thepower control command 209. The UE measures power of a DL_DPCCH signalreceived from the UTRAN to apply a power control command to the powercontrol field of the PC_P 219, and transmits the PC_P to the UTRAN tocontrol transmission power of a downlink channel incoming from theUTRAN.

Reference numerals 221 and 223 denote a control part UL_DPCCH and a datapart UL_DPDCH of the CPCH message, respectively. For a scrambling codefor spreading the CPCH message of FIG. 2, a scrambling code is usedwhich is identical to the scrambling code used for the PC_P 219. For theused scrambling code, the 0^(th) to 38399^(th) scrambling codes oflength 38400 in a unit of 10 ms are used. The scrambling code used forthe message of FIG. 2 can be either a scrambling code used for the AP215 and the CD_P 217, or another scrambling code which is mapped on aone-to-one basis. The channelization code OVSF used for the data part223 of the CPCH message is determined according to a method previouslyappointed between the UTRAN and the UE. That is, since the signature tobe used for the AP and the OVSF code to be used for the UL_DPDCH aremapped, the OVSF code to be used for the UL_DPDCH is determined bydetermining the AP signature to be used. For the channelization codeused by the control part (UL_DPCCH) 221, a channelization code is usedwhich is identical to the OVSF code used by the PC_P. When the OVSF codeto be used for the UL_DPDCH is determined, the channelization code usedby the control part (UL_DPCCH) 221 is determined according to an OVSFcode tree structure.

Referring to FIG. 2, the prior art enables power control of the channelsin order to increase efficiency of the CPCH, which is the uplink commonchannel, and decreases the chance of a collision between uplink signalsfrom the different UEs, by using the CD_P and the CD_ICH. However, inthe prior art, the UE selects all the information for using the CPCH andtransmits the selected information to the UTRAN. This selecting methodcan be performed by combining a signature of the AP, a signature of theCD_P and the CPCH sub-channel, transmitted from the UE. In the priorart, even though the UE requests allocation of the CPCH channel requiredby the UTRAN by analyzing a status of the CPCH, which is presently usedin the UTRAN, by using the CSICH, the fact that the UE previouslydetermines all the information required for transmitting the CPCH andtransmits the determined information will result in a limitation of theallocation of resources of the CPCH channel and a delay in acquiring thechannel.

The limitations on allocation of the CPCH channel are as follows.Although there exist several available CPCHs in the UTRAN, if the UEs inthe UTRAN require the same CPCH, the same AP will be selected. Althoughthe same AP_AICH is received and the CD_P is transmitted again, the UEswhich transmitted the non-selected CD_P should start the process forallocating the CPCH from the beginning. In addition, although the CD_Pselecting process is performed, many UEs still receive the same CD_ICH,increasing a probability that a collision will occur during uplinktransmission of the CPCH. Further, although the CSICH is checked and theUE requests the right to use the CPCH, all of the UEs in the UTRAN whichdesire to use the CPCH receive the CSICH. Therefore, even though anavailable channel is required out of the CPCHs, there is a case whereseveral UEs simultaneously request channel allocation. In this case, theUTRAN cannot but allocate the CPCH requested by one of the UEs, eventhough there are other CPCHs which can be allocated.

With regard to the delay in acquiring the channel, when the case occurswhich has been described with reference to the limitations on allocationof the CPCH channel, the UE should repeatedly perform the CPCHallocation request to allocate the desired CPCH channel. When there isused a method for transmitting the CD_P at a given time for apredetermined time using only one signature for the CD_P introduced toreduce the complexity of the system, it is not possible to process theCD_ICH of other UEs while transmitting and processing the CD_ICH of oneUE.

In addition, the prior art uses one uplink scrambling code inassociation with one signature used for the AP. Thus, whenever the CPCHused in the UTRAN increases in number, the uplink scrambling code alsoincreases in number, causing a waste of the resources.

Meanwhile, in order to efficiently transmit packet data using the commonchannel such as the CPCH channel, a scheduling method for effectivelyassigning and releasing the channel is required. The scheduling methodis used to rapidly release the channel when there is no data on a givenuplink channel, and then assign the released channel to another UE,thereby to prevent unnecessary channel access by the UE and a waste ofthe channel resources.

At present, the maximum length of the packet, which can be transmittedover the CPCH, is broadcasted from the UTRAN to the UE through aparameter NF_max of an RRC (Radio Resource Control) message. In general,the maximum length of the packet that can be transmitted over the CPCHis 64. Therefore, when a frame length of the physical layer is 10 ms andNF_max is set to 64, the UE can transmit the packet data for 640 msafter a success of initial access.

However, since the UTRAN knows only the maximum transmission durationNF_max assigned by itself, the UTRAN reserves (or schedules) a Node Bresource for the maximum transmission duration or defers (or rejects) aresource assignment request from another UE, in expectation of datatransmission from the UE for 640 ms. In this operation, the UTRANstatically monitors data transmitted from the UE, and thus, it is notpossible to effectively guarantee scheduling. That is, even though theUE ends data transmission before expiration of the maximum datatransmission duration NF_max, the UTRAN releases the channel aftermonitoring the corresponding channel until the maximum data durationNF_max expires.

For this reason, the UTRAN increases power of the UE on a falsedetermination that a frame error is occurring from the point where theUE ends data transmission until the point where NF_max expires, therebycausing a waste of the resources. In addition, since the UTRAN cannotrapidly assign the channel to another UE requiring the CPCH, the UErepeats an attempt to access the channel, thus decreasing the overallsystem stability.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide anapparatus and method for transmitting a message over a common channel ina CDMA communication system.

It is another object of the present invention to provide a downlinkacquisition indicator channel (AICH), over which a mobile stationreceiver can receive an acquisition indicator channel with a lowcomplexity.

It is further another object of the present invention to provide amethod for enabling a mobile station to simply detect several signaturestransmitted over the downlink acquisition indicator channel.

It is yet another object of the present invention to provide a channelallocation method for performing efficient power control on an uplinkcommon channel for transmitting a message over a common channel in aCDMA communication system.

It is still another object of the present invention to provide a channelallocation method for rapidly allocating an uplink common channel fortransmitting a message over a common channel in a CDMA communicationsystem.

It is still another object of the present invention to provide areliable channel allocation method for allocating an uplink commonchannel for transmitting a message over a common channel in a CDMAcommunication system.

It is still another object of the present invention to provide a methodfor correcting errors occurring in an uplink common channelcommunication method for transmitting a message over a common channel ina CDMA communication system.

It is still another object of the present invention to provide a methodfor detecting and managing a collision of an uplink between UEs in anuplink common channel communication method for transmitting a messageover a common channel in a CDMA communication system.

It is still another object of the present invention to provide a deviceand method for allocating a channel so as to transmit a message over anuplink common channel in a W-CDMA communication system.

It is still another object of the present invention to provide a deviceand method which can detect an error which has occurred in a channelallocation message or a channel request message in an uplink commonchannel communication method for transmitting a message over a commonchannel in a CDMA communication system.

It is still another object of the present invention to provide a methodfor correcting an error which has occurred in a channel allocationmessage or a channel request message in an uplink common channelcommunication system for transmitting a message over a common channel ina CDMA communication system.

It is still another object of the present invention to provide a deviceand method which uses a power control preamble to detect an error whichhas occurred in a channel allocation message or a channel requestmessage in an uplink common channel communication method fortransmitting a message over a common channel in a CDMA communicationsystem.

It is still another object of the present invention to provide anapparatus and method for transmitting a single combined code to detect acollision of an uplink common packet channel and to allocate the uplinkcommon packet channel in a CDMA communication system.

It is still another object of the present invention to provide a methodfor dividing uplink common channels into a plurality of groups andefficiently managing each group.

It is still another object of the present invention to provide a methodfor dynamically managing radio resources allocated to the uplink commonchannels.

It is still another object of the present invention to provide a methodfor efficiently managing uplink scrambling codes allocated to the uplinkcommon channels.

It is still another object of the present invention to provide a methodin which the UTRAN informs the UE of the present status of the uplinkcommon channel.

It is still another object of the present invention to provide a deviceand method for transmitting information, with increased reliability,used when the UTRAN informs the UE of the present status of the uplinkcommon channel.

It is still another object of the present invention to provide anencoding/decoding apparatus and method for transmitting, with increasedreliability, information used when the UTRAN informs the UE of thepresent status of the uplink common channel.

It is still another object of the present invention to provide a deviceand method for enabling the UE to rapidly determine the present statusof the uplink common channel transmitted from the UTRAN.

It is still another object of the present invention to provide a methodin which the UE determines whether to use the uplink common channeldepending on the status information of the uplink common channel,transmitted from the UTRAN.

It is still another object of the present invention to provide anapparatus and method for allocating an uplink common channel using AP(Access Preamble) and CA (Channel Allocation) signals.

It is still another object of the present invention to provide a mappingmethod for allocating an uplink common channel using the AP and CAsignals:

It is still another object of the present invention to provide a methodfor operating an upper layer of the UE to transmit data over an uplinkcommon packet channel.

It is still another object of the present invention to provide a methodfor indicating a data rate of an uplink common channel in combinationwith an AP signature and an access slot.

It is still another object of the present invention to provide a methodfor indicating the number of transmission data frames of an uplinkcommon channel in combination with the AP signature and the access slot.

It is still another object of the present invention to provide a methodin which the UTRAN allocates an uplink common channel to the UEaccording to a group of the maximum data rates per CPCH set.

It is still another object of the present invention to provide anapparatus and method for simultaneously performing uplink common channelallocation and uplink outer-loop power control.

It is still another object of the present invention to provide anapparatus and method for transmitting the maximum data rate over a CPCHstatus indicator channel (CSICH).

It is still another object of the present invention to provide anapparatus and method for transmitting CPCH availability informationthrough the CSICH.

It is still another object of the present invention to provide anapparatus and method for simultaneously transmitting the maximum datarate and the CPCH availability information through the CSICH.

It is still another object of the present invention to provide anapparatus and method for indicating an end of frame on a common packetchannel (CPCH) in a CDMA communication system.

It is still another object of the present invention to provide anapparatus and method for indicating an end of data transmission througha CPCH channel when data transmission from the UE is ended beforeexpiration of the maximum transmission duration.

To achieve the above objects, there is provided a method for a UE toindicate an end of transmitting data frames in order to enable a UTRANto assign a common packet channel to another UE in a CDMA mobilecommunication system. The method comprises requesting assignment of anyone of common packet channels assignable in the UTRAN; assigning acommon packet channel by the UTRAN in response to the to request;sequentially transmitting the data frames and their associated controlframes over the assigned common packet channel; and transmitting atleast one control frame, in an appointed field of which a given bitpattern appointed with the UTRAN is registered, in order to inform theUTRAN of an end of data transmission upon completing data transmissionthrough the data frames.

Preferably, the appointed field is any one of a TFCI field, a pilotfiled, a feed back information (FBI) field, and a transport powercontrol (TPC) field.

Preferably, the appointed field includes at least two of TFCI, pilot,FBI and TPC fields.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription when taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a diagram for explaining how to transmit and receive a trafficsignal over a RACH out of the conventional asynchronous uplink commonchannels;

FIG. 2 is a diagram illustrating a signal transmission procedure ofconventional downlink and uplink channels;

FIG. 3 is a diagram illustrating a signal flow between a UE and a UTRANto establish an uplink common channel according to an embodiment of thepresent invention;

FIG. 4 is a diagram illustrating a structure of a CSICH channelaccording to an embodiment of the present invention;

FIG. 5 is a block diagram illustrating a CSICH encoder for transmittingan SI bit according to an embodiment of the present invention;

FIG. 6 is a block diagram illustrating a CSICH decoder corresponding tothe CSICH encoder of FIG. 5;

FIG. 7 is a diagram illustrating a structure of an access slot used fortransmitting an access preamble according to an embodiment of thepresent invention;

FIG. 8A is a diagram illustrating a structure of an uplink scramblingcode according to the prior art;

FIG. 8B is a diagram illustrating a structure of an uplink scramblingcode according to an embodiment of the present invention;

FIGS. 9A and 9B are diagrams illustrating a structure of an accesspreamble for a common packet channel according to an embodiment of thepresent invention, and a scheme for generating the same;

FIGS. 10A and 10B are diagrams illustrating a channel structure of acollision detection preamble according to an embodiment of the presentinvention, and a scheme for generating the same;

FIGS. 11A and 11B are diagrams illustrating structure of a channelallocation indicator channel (CA_ICH) according to an embodiment of thepresent invention, and a scheme for generating the same;

FIG. 12 is a diagram illustrating an AICH generator according to anembodiment of the present invention;

FIGS. 13A and 13B are diagrams illustrating a CA_ICH according to anembodiment of the present invention, and a scheme for generating thesame;

FIG. 14 is a diagram illustrating a scheme for simultaneouslytransmitting a collision detection indicator channel (CD_ICH) and theCA_ICH by allocating different channelization codes having the samespreading factor according to an embodiment of the present invention;

FIG. 15 is a diagram illustrating a scheme for spreading the CD_ICH andthe CA_ICH with the same channelization code and simultaneouslytransmitting the spread channels using the different signature groupsaccording to another embodiment of the present invention;

FIG. 16 is a diagram illustrating a CA_ICH receiver of a user equipment(UE) for a signature structure according to an embodiment of the presentinvention;

FIG. 17 is a diagram illustrating a receiver structure according toanother embodiment of the present invention;

FIG. 18 is a diagram illustrating a transceiver of a UE according to anembodiment of the present invention;

FIG. 19 is a diagram illustrating a transceiver of a UTRAN according toan embodiment of the present invention;

FIG. 20 is a diagram illustrating a slot structure of a power controlpreamble (PC_P) according to an embodiment of the present invention;

FIG. 21 is a diagram illustrating a structure of the PC_P shown in FIG.20;

FIG. 22A is a diagram illustrating a method for transmitting a channelallocation confirmation message or a channel request confirmationmessage from the UE to the UTRAN using the PC_P according to anembodiment of the present invention;

FIG. 22B is a diagram illustrating a structure of the uplink scramblingcodes used in FIG. 22A.

FIG. 23 is a diagram illustrating a method for transmitting a channelallocation confirmation message or a channel request confirmationmessage from the UE to the UTRAN using the PC_P according to anotherembodiment of the present invention;

FIG. 24A is a diagram illustrating a method for transmitting a channelallocation confirmation message or a channel request confirmationmessage from the UE to the UTRAN using the PC_P according to anembodiment of the present invention;

FIG. 24B is a diagram illustrating a tree structure of PC_Pchannelization codes in one-to-one correspondence to the signature ofthe CA_ICH or the CPCH channel number according to an embodiment of thepresent invention;

FIG. 25A is a diagram illustrating a method for transmitting a channelallocation confirmation message or a channel request confirmationmessage from the UE to the UTRAN using the PC_P according to anotherembodiment of the present invention;

FIG. 25B is a diagram illustrating structures of the uplink scramblingcodes used for AP, CD_P, PC_P and CPCH message part by the UEs whentransmitting the PC_P using the method of FIG. 25A;

FIGS. 26A to 26C are flowcharts illustrating a procedure for allocatinga common packet channel in the UE according to an embodiment of thepresent invention;

FIGS. 27A to 27C are flowcharts illustrating a procedure for allocatinga common packet channel in the UTRAN according to an embodiment of thepresent invention;

FIGS. 28A and 28B are flow charts illustrating a procedure for setting astable CPCH using the PC_P, performed in the UE, according to anembodiment of the present invention;

FIGS. 29A to 29C are flow charts illustrating a procedure for setting astable CPCH using the PC_P, performed in the UTRAN, according to anembodiment of the present embodiment of the present invention;

FIGS. 30A and 30B are flow charts illustrating a procedure forallocating information necessary for the CPCH to the UE using an APsignature and a CA message according to an embodiment of the presentinvention;

FIG. 31 is a block diagram illustrating a CSICH decoder according toanother embodiment of the present invention;

FIG. 32 is a flow chart illustrating a procedure for transmitting dataover an uplink common packet channel, performed in an upper layer of theUE, according to an embodiment of the present invention;

FIG. 33 is a diagram illustrating a signal and data flow between the UEand the UTRAN to perform uplink outer-loop power control according to anembodiment of the present invention;

FIG. 34 is a diagram illustrating a structure of a lur data frame foruplink outer-loop power control according to an embodiment of thepresent invention;

FIG. 35 is a diagram illustrating a structure of lur data frame foruplink outer-loop power control according to an embodiment of thepresent invention;

FIG. 36 is a diagram illustrating a structure of a lur control frame foruplink outer-loop power control according to an embodiment of thepresent invention;

FIG. 37 is a diagram illustrating a structure of a lub control frame foruplink outer-loop power control according to an embodiment of thepresent invention;

FIG. 38 is a diagram illustrating a frame structure used when the UEinforms the UTRAN of an end of data transmission, according to anembodiment of the present invention;

FIG. 39 is a diagram illustrating a procedure for releasing a commonpacket channel according to an embodiment of the present invention;

FIG. 40 is a diagram illustrating a procedure for releasing a commonpacket channel according to another embodiment of the present invention;

FIG. 41 is a diagram illustrating a procedure for releasing a commonpacket channel according to further another embodiment of the presentinvention;

FIG. 42 is a diagram illustrating a detailed transmission scheme of thePCPCH shown in FIG. 41; and

FIG. 43 is a diagram illustrating a novel process for releasing thecommon packet channel in comparison with the conventional process forreleasing the common packet channel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Preferred embodiments of the present invention will be described hereinbelow with reference to the accompanying drawings. In the followingdescription, well-known functions or constructions are not described indetail since they would obscure the invention in unnecessary detail.

In a CDMA communication system according to the preferred embodiments ofthe present invention, in order to transmit a message to the UTRAN overthe uplink common channel, the UE checks a status of the uplink commonchannel through the uplink common channel and then transmits a desiredaccess preamble (AP) to the UTRAN. Upon acquisition of the AP, the UTRANtransmits a response signal (or access preamble acquisition indicatorsignal) in acknowledgment of the AP over the access preamble acquisitionindicator channel (AP_AICH). Upon receipt of the access preambleacquisition indicator signal, the UE transmits a collision detectionpreamble (CD_P) to the UTRAN, if the received access preambleacquisition indicator signal is an ACK signal. Upon receipt of thecollision detection preamble CD_P, the UTRAN transmits to the UE aresponse signal (or a collision detection indicator channel (CD_ICH)signal) for the received collision detection signal and a channelallocation (CA) signal for an uplink common channel. Upon receipt of theCD_ICH signal and the channel allocation signal from the UTRAN, the UEtransmits an uplink common channel message over a channel allocatedaccording to the channel allocation message, if the CD_ICH signal is anACK signal. Before transmission of this message, it is possible totransmit a power control preamble (PC_P). In addition, the UTRANtransmits power control signals for the power control preamble and theuplink common channel message, and the UE controls transmission power ofthe power control preamble and the uplink common channel messageaccording to the power control command received over the downlinkchannel.

In the above description, if the UE has several APs which can betransmitted, a preamble transmitted by the UE can be one of them, andthe UTRAN generates AP_AICH in response to the AP and may transmitCA_ICH for allocating the above-stated channel after transmitting theAP_AICH.

FIG. 3 shows a signal flow between the UE and the UTRAN to establish anuplink common packet channel (CPCH) or an uplink common channel proposedin the preferred embodiments of the present invention. In the preferredembodiments of the present invention, it will be assumed that an uplinkcommon packet channel is used for the uplink common channel. However, adifferent common channel other than the uplink common packet channel canalso be used for the uplink common channel.

Referring to FIG. 3, the UE, after time synchronization with thedownlink through a downlink-broadcasting channel, acquires informationrelated to the uplink common channel or the CPCH. The informationrelated to the uplink common channel includes information about thenumber of scrambling codes and signatures used for the AP, and AICHtiming of the downlink. Reference numeral 301 indicates a downlinksignal transmitted from the UTRAN to the UE, and reference numeral 331indicates an uplink signal transmitted from the UE to the UTRAN. Whenthe UE attempts to transmit a signal over the CPCH, the UE firstreceives information about a status of the CPCHs in the UTRAN over aCPCH status indicator channel (CSICH). Conventionally, the informationabout a status of the CPCHs refers to information about the CPCHs in theUTRAN, i.e., the number of CPCHs and availability of the CPCHs. However,in the preferred embodiments of the present invention, the informationabout a status of the CPCHs refers to information about the maximum datarate available for each CPCH, and how many multi-codes can betransmitted when the UE transmits multi-codes over one CPCH. Even wheninformation about availability of each CPCH is transmitted as in theprior art, it is possible to use the channel allocation method accordingto the present invention. The above data rate is 15 Ksps (symbols persecond) up to 960 Ksps in the W-CDMA asynchronous mobile communicationsystem, and the number of multi-codes is 1 to 6.

CPCH Status Indicator Channel (CSICH)

Now, a detailed description will be made of a CPCH status indicatorchannel (CSICH) transmitted to the UE by the UTRAN to allocate the CPCHaccording to an embodiment of the present invention. The presentinvention proposes a method in which the UTRAN transmits use-statusinformation of physical channels (hereinafter, referred to as commonpacket channel) and maximum data rate information to the UE over theCSICH, so as to be allocated a desired physical channel.

A description of the CSICH will be given in accordance with the presentinvention in the following order.

First, a structure of the CSICH for transmitting the use-statusinformation of the CPCH and the maximum data rate information, and ascheme for generating the same will be described.

Second, a method for transmitting the use-status information of the CPCHand the maximum data rate using the CSICH will be described.

A detailed description will be made regarding a structure of the CSICHfor transmitting the use-status information of the CPCH and the maximumdata rate, and a scheme for generating the same.

FIG. 4 shows a structure of the CSICH channel according to an embodimentof the present invention. The CSICH shown in FIG. 4 is a channel fortransmitting information about a status of the CPCHs within the UTRAN byusing the last 8 unused bits out of the access preamble acquisitionindicator channel (AICH). The AICH is a channel used by a W-CDMA UTRANto receive an access preamble (AP) from the UE and send a response tothe received AP. The response may be provided as ACK or NAK. The AP is achannel used by the UE to inform, when there exists data to betransmitted over the CPCH, the UTRAN of existence of the transmissiondata.

FIG. 4 shows a channel structure the CSICH. Referring to FIG. 4,reference numeral 431 indicates a structure where 32-bit AP_AICH part(AI part) and 8-bit CSICH part (Unused part) are included in one accessslot. The access slot is a reference slot for transmitting and receivingthe AP and AP_AICH in the W-CDMA system, and 15 access slots areprovided for a 20 ms frame as shown by reference numeral 411. Thus, oneframe has a length of 20 ms and each access slot in the frame has alength of 5120 chips. As stated above, reference numeral 431 indicates astructure where the AP_AICH and the CSICH are transmitted in one accessslot. When the AP_AICH part has no data to transmit, the AP_AICH part isnot transmitted. The AP_AICH and the CSICH are spread with a specificchannelization code by a given multiplier. The specific channelizationcode is a channelization code designated by the UTRAN, and the AP_AICHand the CSICH use the same channelization code. In this embodiment ofthe present invention, the spreading factor (SF) of the channelizationcode is assumed to be 256. The spreading factor means that the OVSF codehaving a length of spreading factor per symbol is multiplied by theAP_AICH and the CSICH. Meantime, it is possible to transmit differentinformation over the AP_AICH and the CSICH at every access slot, and 120bits of information (8 bits*15 slots/frame=120 bits/frame) on the CSICHare transmitted for every 20 ms frame. In the foregoing description, thelast 8 unused bits of the AP_AICH are used when transmitting the CPCHchannel state information over the CSICH. However, since the CD_ICH isidentical to the AP_AICH in structure, it is also possible to transmitthe CPCH channel status information to be transmitted over the CSICHthrough the CD_ICH.

As stated above, 120 bits are allocated to the CSICH according to anembodiment of the present invention in one frame, and the use-statusinformation of the CPCH and the maximum data rate information aretransmitted over the CSICH. That is, one frame includes 15 slots, and 8bits are allocated for the CSICH in each slot.

A detailed description will now be made regarding a mapping scheme andmethod for transmitting, in the UTRAN, the use-status information of theCPCH and the maximum data information rate using the CSICH. That is, thepresent invention includes a method for mapping the use-statusinformation of the CPCH and the maximum data rate information to 120bits allocated to one frame.

Further, in this embodiment of the present invention, informationtransmitted over the CSICH by the UTRAN is, as stated above, comprisedof the maximum data rate information of the CPCH and the use-statusinformation of the respective PCPCHs used in the UTRAN. Meanwhile, themaximum data rate information of the CPCH may be transmitted withinformation about the number of multi-codes used when multi-codetransmission is used in one CPCH.

First, a detailed description will be given regarding a method fortransmitting the maximum data rate information of the CPCH in the UTRANaccording to an embodiment of the present invention. Herein, thedescription will be made separately for one case wherein the multi-codetransmission is used in one CPCH and another case wherein the multi-codetransmission is not used in one CPCH.

Table 1 below shows an exemplary method for transmitting the informationon the number of the multi-codes used when the multi-code transmissionis used in one CPCH, together with the maximum data rate information ofthe CPCH out of the information transmitted over the SCICH. Table 1shows 7 data rates of SF4, SF8, SF16, SF32, SF64, SF128 and SF256 forthe maximum data rate of the CPCH, by way of example.

TABLE 1 Information Bit Expression Data Rate 15 Ksps (SF256) 0000(000)Data Rate 30 Ksps (SF128) 0001(001) Data Rate 60 Ksps (SF64)  0010(010)Data Rate 120 Ksps (SF32) 0011(011) Data Rate 240 Ksps (SF16) 0100(100)Data Rate 480 Ksps (SF8)  0101(101) Data Rate 960 Ksps (SF4)  0110(110)Number of Multi-codes = 2 0111 Number of Multi-codes = 3 1000 Number ofMulti-codes = 4 1001 Number of Multi-codes = 5 1010 Number ofMulti-codes = 6 1011

In Table 1, the multi-code has a spreading factor of 4, and it isspecified in the W-CDMA system that only the spreading factor of 4 canbe used for the channelization code of the UE, when the UE performs themulti-code transmission. As shown in Table 1, in this embodiment of thepresent invention, the maximum data rate information of the CPCH,transmitted over the CSICH, may be expressed with 4 bits. As a methodfor transmitting the 4 bits over the CSICH to the UE which desires touse the CPCH, it is possible to repeatedly transmit the 4 bits twice inone 8-bit access slot allocated to the CSICH or using a (8,4) codingmethod.

In the foregoing description given with reference to Table 1, 4 bits aretransmitted including one bit for informing the UE of the number of themulti-codes according to the use of the multi-code. However, when themulti-code is not used, it is also possible to transmit only the 3 bitsindicated in parentheses in Table 1. Here, the 3-bit informationindicates the maximum data rate information of the CPCH. In this case,it is possible to transmit 8 symbols at one slot by (8,3) coding or torepeat the 3 bits twice, and repeat once more 1 symbol out of the 3bits.

Next, a detailed description will be made regarding a method fortransmitting the use-status information of the PCPCH in the UTRANaccording to an embodiment of the present invention.

The PCPCH use-status information to be transmitted is informationindicating whether the respective PCPCHs used in the UTRAN are used ornot, and the number of the bits of the PCPCH use-status information isdetermined depending on the total number of the PCPCHs used in theUTRAN. The bits of the PCPCH use-status information can also betransmitted over the CSICH, and to this end, it is necessary to proposea method for mapping the bits of the PCPCH use-status information to apart allocated to the CSICH. In the following description, the bits inthe part allocated to the CSICH out of the bits in the frame will bereferred to as CSICH information bits. This mapping method can bedetermined depending on the number of the CSICH information bits and thetotal number of the PCPCHs used in the UTRAN, i.e., the number of thebits of the PCPCH use-status information.

First, there is a case where the number of the bits of the PCPCHuse-status information due to the total number of the PCPCHs used in theUTRAN is identical to the number of the CSICH information bits in oneslot when transmitting the PCPCH use-status information out of theinformation which can be transmitted over the CSICH. For example, thiscorresponds to a case where the number of the CSICH information bits inone slot is 8 and the total number of the PCPCHs used in the UTRAN is 8.In this case, it is possible to repeatedly transmit the statusinformation of every PCPCH used in the UTRAN 15 times for one frame bymapping one PCPCH use-status information bit to the one CSICHinformation bit.

Describing how to use the CSICH information bits in the foregoing case,the 3^(rd) CSICH information bit out of a plurality of the CSICHinformation bits is the use-status information indicating whether the3^(rd) PCPCH out of a plurality of the PCPCHs used in the UTRAN is inuse or not. Therefore, transmitting ‘0’ as a value of the 3^(rd) CSICHinformation bit indicates that the 3^(rd) PCPCH is presently in use.Alternatively, transmitting ‘1’ as a value of the 3^(rd) CSICHinformation bit indicates that the 3^(rd) PCPCH is presently not in use.The meaning of the values ‘0’ and ‘1’ of the CSICH information bitindicating whether the PCPCH is in use or not, may be interchanged.

Next, there is a case where the number of the PCPCH use-statusinformation bits due to the total number of the PCPCHs used in the UTRANis larger than the number of the CSICH information bits in one slot whentransmitting the PCPCH use-status information out of the informationwhich can be transmitted over the CSICH. In this case, it is possible touse a multi-CSICH method for transmitting the use-status information ofthe PCPCH over at least two CSICHs and another method for transmittingmultiple slots or multiple frames over one channel.

In the first method for transmitting the PCPCH use-status informationover at least two CSICHs, the PCPCH use-status information istransmitted through CSICH information bits of different channels in aunit of 8 bits. Here, the CSICH information bits of the differentchannels correspond to the last 8 unused bits out of the bitsconstituting one access slot of AP_AICH, RACH_IACH and CD/CA_ICH. Forexample, when the total number of the PCPCHs used in the UTRAN is 24,the 24 PCPCHs are divided in a unit of 8 PCPCHs and the statusinformation of the first 8 PCPCHs is transmitted through the last 8unused bits out of the bits constituting one access slot of the AP_AICH.The status information of the next 8 PCPCHs is transmitted through thelast 8 unused bits out of the bits constituting one access slot of theRACH_AICH. The status information of the last 8 PCPCHs is transmittedthrough the last 8 unused bits out of the bits constituting one accessslot of the CD/CA_ICH.

As stated above, when there are many PCPCH use-status information bitsto transmit, it is possible to segment the PCPCH use-status informationand transmit the segmented information using all or some of the proposedchannels AP_AICH, RACH_AICH and CD/CA_ICH. Since the channels AP_AICH,RACH_AICH and CD/CA_ICH use unique downlink channelization codes, the UEcan identify these channels during reception. That is, the UE canreceive a multi-CSICH.

In addition, when there are many PCPCH use-status information bits, itis also possible to use a method for assigning a plurality of downlinkchannelization codes to a plurality of CSICHs and transmitting theCSICHs to the UE.

In the second method for transmitting the PCPCH use-status informationover at least two CSICHs, the PCPCH use-status information istransmitted through plural slots or plural frames which are transmittedover one channel in a unit of 8 bits.

For example, if the number of the PCPCH use-status information bits tobe transmitted is 60, the 60 bits can be repeatedly transmitted onlytwice to the CSICH information bits in one frame comprised of 120 bits.Repeating the 60 bits twice may decrease a reliability of the PCPCHuse-status information. To solve this problem, it is possible torepeatedly transmit the 60-bit CSICH information over the next frame. Itis also possible to divide the 60 bits into 30 bit segments, repeatedlytransmit the first 30 bits 4 times to the CSICH information bits in oneframe, and then, repeatedly transmits the remaining 30 bits 4 times tothe CSICH information bit in the next CSICH frame.

Finally, there is a case where the number of the PCPCH use-statusinformation bits due to the total number of the PCPCHs used in the UTRANis smaller than the number of the CSICH information bits in one slotwhen transmitting the PCPCH use-status information out of theinformation which can be transmitted over the CSICH. In this case, it ispossible to transmit the PCPCH use-status information by partially usingthe 120-bit CSICH information allocated in one frame. That is, the PCPCHuse-status information is transmitted by reducing the number of CSICHinformation bits for transmitting the PCPCH use-status information.

For example, if the PCPCH use-status information to be transmitted iscomprised of 4 bits, the PCPCH use-status information is transmitted inthe first 4 bits out of the 8 CSICH information bits in the respectiveaccess slots constituting one frame and the PCPCH use-status informationis not transmitted in the remaining 4 bits. It is possible to transmitnull bits known by the UE to the CSICH information bits which do nottransmit the PCPCH use-status information. As another example, it ispossible to repeatedly transmit 2-bit PCPCH use-status information and 2null bits in the 8-bit CSICH information in the respective access slotsconstituting one frame. Otherwise, it is also possible to repeatedlytransmit 1-bit PCPCH use-status information and 1 null bit in the 8-bitCSICH information in the respective access slots constituting one frame.In addition, it is possible to transmit the PCPCH use-status informationin the entire 8-bit CSICH information in an initial access slotconstituting one frame, and then, transmit null bits in the entire 8-bitCSICH information in the next access slot. That is, this is a method ofalternately transmitting the PCPCH use-status information and the nullbits at a period of one access slot. Therefore, the PCPCH use-statusinformation is transmitted over the odd-numbered access slots in oneframe and the null data is transmitted over the even-numbered accessslots. Alternatively, the PCPCH use-status information can betransmitted over the even-numbered access slots and the null data can betransmitted over the odd-numbered access slots. The null bits can bereplaced with discontinuous transmission (DTX), which means no datatransmission.

In the foregoing case, the UE will receive the PCPCH use-statusinformation and the null bits over one frame. If the UTRAN uses DTXinstead of the null bits, the UE can use discontinuous reception (RDX),which means not receiving data in a non-data transmission period.

In the foregoing examples, the UTRAN transmits the PCPCH use-statusinformation to the UEs, so as to enable each UE that desires to transmitdata over the CPCH, to be able to monitor the use-status information ofthe present PCPCH. That is, upon receipt of the PCPCH use-statusinformation transmitted over the CSICH, the UE desiring to use the CPCHcan determine whether the PCPCHs available in the UTRAN are available ornot. Therefore, the UE desiring to use the CPCH can request assignmentof the PCPCH, use of which can be approved by the present UTRAN. The UEdesiring to use the CPCH selects an AP signature for requestingassignment of a desired one of the PCPCHs, availabilities of which areconfirmed from the PCPCH use-status information, and transmits theselected AP signature to the UTRAN. Meanwhile, the UTRAN transmits ACKor NAK in response to the AP signature over the AP_AICH. Also, as statedabove, the UTRAN transmits the PCPCH use-status information over theAP_AICH. Upon receipt of ACK from the UTRAN over the AP_AICH, the UEselects again a given CD signature and transmits CD_P. The UTRAN thentransmits a CA signal together with ACK or NAK in response to the CD_P.Upon receipt of the ACK signal and the CA signal for the CD from theUTRAN, the UE compares the CPCH allocated to it with the resultconfirmed in the monitoring process. If it is determined that theallocated PCPCH is already in use, it means that the CA has an error.Therefore, the UE can transmit no signal over the allocated PCPCH. Asanother method, after the UE has allocated the PCPCH in the foregoingprocedure, if it is determined that the allocated PCPCH which was not inuse in the previous monitoring process is indicated as being in use inthe present monitoring process, it is noted that the CA is normallyreceived. Otherwise, if the allocated PCPCH was already in use in theprevious monitoring process or is not indicated as being in use in thepresent monitoring process, it is noted that the CA has an error. Thelatter monitoring process can be performed after transmission of thePCPCH or a message, and upon detecting the error, the UE stops signaltransmission.

Heretofore, a description is made regarding one method in which theUTRAN transmits the maximum available data rate information to the UE,and another method in which the UTRAN transmits the use-statusinformation of the PCPCH to the UE.

Finally, it is also possible to transmit the two kinds of information atthe same time. Several embodiments of this method will be describedbelow.

First Embodiment

In a first embodiment of the method for transmitting the two kinds ofinformation at the same time, some of the slots constituting one frameof the CSICH are used to transmit the maximum data rate information andthe remaining slots are used to transmit the use-status information ofthe PCPCH. One frame of the CSICH used in the present asynchronousstandard may have the same length as one access frame. The frame lengthis 20 ms and includes 15 access slots. As an example of this method, itis assumed that the number of the information bits needed to transmitthe maximum data rate used in the UTRAN is 3 and the number of thePCPCHs used in the UTRAN is 40. In this case, the UTRAN can use 3 of the15 slots constituting one CSICH frame in transmitting the maximum datarate information, and use the remaining 12 slots in transmitting thePCPCH use-status information. That is, the UTRAN can transmit 24-bitmaximum data rate information and 96-bit PCPCH use-status informationover one frame.

Therefore, if it is assumed that the same data is transmitted to the Ichannel and the Q channel in the CSICH, it is possible to repeatedlytransmit 3-bit maximum data rate information 4 times in total. Inaddition, it is possible to transmit once the 40-bit use-statusinformation indicating whether the individual PCPCHs used in the UTRANare available or not, through the I channel and Q channel. On thecontrary, if it is assumed that the different data is transmittedthrough the I channel and the Q channel, it is possible to transmit3-bit maximum data rate information 8 times in total. In addition, it ispossible to repeatedly transmit twice the use-status information of therespective PCPCHs used in the UTRAN. In the first method stated above,the positions of a slot for transmitting the maximum data rateinformation and a slot for transmitting the use-status information ofthe PCPCHs used by the UTRAN may be arranged at random by the UTRAN ormay be previously determined.

As one example of arranging the slot positions, the maximum data rateinformation can be transmitted through 0^(th), 5^(th) and 10^(th) slotsout of the 15 access slots in one CSICH frame, and the PCPCH use-statusinformation can be transmitted through the remaining slots. As anotherexample, it is also possible to transmit the maximum data rateinformation through the 0^(th), 1^(st) and 2^(nd) slots and theuse-status information of the PCPCHs used in the UTRAN through the3^(rd) to 14^(th) slots. The above-stated several slots are allocatedfor the maximum data rate information, and how many remaining slots areto be allocated for the PCPCH use-status information is determined byconsidering the number of the PCPCHs used in the UTRAN and the repeatingfrequency of the maximum data rate. In addition, it is also possible totransmit the maximum data rate information and the PCPCH use-statusinformation by segmenting the information into several CSICH framesaccording to the amount of the information. Before transmission of theCSICH, an agreement is previously made with the UE on which informationis to be transmitted in which slot.

Second Embodiment

In a second embodiment of the method for transmitting the two kinds ofinformation at the same time, the 8 CSICH information bits transmittedin one access slot are divided so as to use several information bits inindicating the maximum data rate and the remaining information bits inindicating the PCPCH use-status information.

For example, when the same bit is transmitted through the I channel andthe Q channel, the first 2 bits of one access slot can be used totransmit the information on the maximum data rate available for thePCPCH of the UTRAN, and the remaining 6 bits can be used to transmit theuse-status information of the PCPCHs of the UTRAN. Therefore, 1 bit ofthe maximum data rate information is transmitted through one access slotand 3 bits of the PCPCH use-status information are transmitted throughone access slot.

However, when the different bits are transmitted through the I channeland the Q channel, it is possible to transmit the maximum data rateinformation and the PCPCH use-status information twice as compared withthe case where the same bit is transmitted through the I channel and theQ channel.

In the foregoing second embodiment, the first 2 bits of one access slotare used to transmit the maximum data rate of the PCPCH and theremaining 6 bits are used to transmit the PCPCH use-status information.However, various modifications may be made: for example, 6 bits of oneaccess slot are used to transmit the maximum data rate information and 2bits of one access slot are used to transmit the PCPCH use-statusinformation. That is, the number and the positions of the bits used totransmit the maximum data rate information of the PCPCH and the PCPCHuse-status information can be determined by the UTRAN and notified tothe UE. When the number and the positions of the bits used to transmitthe maximum data rate information of the PCPCH and the PCPCH use-statusinformation are determined, an agreement is made with the UE beforetransmission of the CSICH.

In addition, the UTRAN can transmit the two kinds of information over aplurality of access slots or a plurality of frames. Transmitting the twokinds of information over a plurality of frames is performed when thetwo kinds of information have a large volume or to increase areliability of the information. The UTRAN may determine the number ofaccess slots for transmitting the two kinds of information, consideringthe number of bits needed to transmit the maximum data rate informationand the PCPCH use-status information. The number of the frames fortransmitting the two kinds of information is also determined consideringthe number of bits needed to transmit the maximum data rate informationand the PCPCH use-status information.

Third Embodiment

In a third embodiment of the method for transmitting the two kinds ofinformation at the same time, the information on the maximum data rateavailable for the PCPCH and the PCPCH use-status information aretransmitted through a plurality of CSICHs which may be simultaneouslytransmitted. For example, the maximum data rate information istransmitted through any one of the CSICHs and the PCPCH use-statusinformation is transmitted through the other CSICHs. As one example, thetransmitted CSICHs may be distinguished with the downlink channelizationcodes or the uplink channelization codes. As another example, it is alsopossible to transmit 40 CSICH information bits within one access slot byallocating a separate channelization code to one CSICH. If a separatechannelization code is allocated to one CSICH as stated above, it ispossible to transmit the maximum data rate information of the PCPCHtogether with the PCPCH use-status information within one access slot.

In the foregoing third embodiment, the UTRAN may determine the number ofthe CSICHs to be transmitted, considering the maximum data rateinformation of the PCPCH, the information on the total number of thePCPCHs used in the UTRAN, and a reliability of the above information.

Fourth Embodiment

In a fourth embodiment of the method for transmitting the two kinds ofinformation at the same time, the information is transmitted usingplural frames. That is, all the CSICH information bits in one frame areused to transmit the information on the maximum data rate available forthe PCPCH, and all the CSICH information bits in the other frames areused to transmit the use-status information of the PCPCHs used in theUTRAN.

In this embodiment, the UTRAN can determine the number of frames fortransmitting the maximum data rate information of the PCPCH and thenumber of frames for transmitting the PCPCH use-status information,considering a quantity of the information to be transmitted over theCSICH and a reliability of the information quantity. Here, an agreementon the determined results is previously made with the UE.

Fifth Embodiment

In a fifth embodiment of the method for transmitting the two kinds ofinformation at the same time, the maximum data rate information istransmitted to a bit in a previously appointed position out of the CSICHinformation bits. That is, the maximum data rate information of thePCPCH is transmitted through the CSICH information bits in the positionspreviously agreed between the UTRAN and the UE, out of the CSICHinformation bits in the frame. Further, the use-status information ofthe PCPCHs used in the UTRAN is transmitted through the remaining CSICHinformation bits excepting the CSICH information bits used fortransmitting the maximum data rate information.

In the fifth embodiment, an exemplary method for recording the maximumdata rate information of the PCPCH in the CSICH information bits beforetransmission is expressed by Equation (1) below:

$\begin{matrix}{d_{i}\left\{ {{{\begin{matrix}0 \\1\end{matrix}i} = 0},1,\ldots\mspace{14mu},{I - 1}} \right.} & (1)\end{matrix}$where i indicates the number of the maximum data rate information bitsand d_(i) indicates the maximum data rate information to be transmitted.For example, if d_(i)={1 0 1} with I=3, then d₀=1, d₁=0 and d₂=1.

In the fifth embodiment, an exemplary method for recording the PCPCHuse-status information in the CSICH information bits before transmissionis expressed by Equation (2) below:

$\begin{matrix}{p_{j} = \left\{ {{{\begin{matrix}0 \\1\end{matrix}j} = 0},1,\ldots\mspace{14mu},{J - 1}} \right.} & (2)\end{matrix}$where J indicates the total number of the PCPCHs used per CPCH set inthe UTRAN, and p_(j) indicates the use-status information of therespective PCPCHs. Hence, the number of the PCPCHs is 16 and the PCPCHuse-status information, indicating whether the respective PCPCHs areused or not, is p_(j)={0 0 1 1 1 0 0 1 0 1 0 1 1 0 0}.

Equation (3) below shows a method for recording ‘0’ in the remainingbits except the bits needed to repeatedly transmit, for a preset numberof times, the maximum data rate information together with the PCPCHuse-status information out of the total CSICH information bits, when thetotal number N of the CSICH information bits, which can be transmittedover one frame, are determined.e _(k) =0,k=0,1, . . . ,K−1ore _(k) =1,k=0,1, . . . ,K−1  (3)where K indicates the remaining CSICH information bits other than thebits used to transmit the maximum data rate information available forthe PCPCH and the use-status information of the respective PCPCHs usedin the UTRAN. In particular, K indicates the number of bits experiencingzero-fading or DTX.

Equation (4) below shows the total number N of the CSICH informationbits which can be transmitted over one frame.N=I*R+J+K  (4)

When N defined in Equation (4) is less than 120, it is selected fromdivisors of 120. For example, N=3, 5, 15, 30 and 60. In Equation (4), Rindicates how many times the maximum data rate information bits are tobe repeated in one access frame. In Equation (4), I and J are determinedduring system implementation and notified to the UE by the UTRAN. Thus,these values can be previously known. That is, these values are givenfrom the upper layer.

As one method for determining the value N, when I and J are known, thevalue N may be determined as the minimum number among the values 3, 5,15, 30 and 60, which satisfy the condition of N≧I+J. Alternatively, theUTRAN transmits the value N or R to the UE in addition to the values Iand J, so that the value R or N and the value K may be determined fromEquation (4).

The order of determining the values N and R is given in three methods asfollows.

In a first method, the value N is determined by the given values I andJ, and the value R can be determined as a quotient obtained by dividing(N−J) by I, as expressed by Equation (5) below.

$\begin{matrix}{R = \left\lfloor \frac{\left( {N - J} \right)}{I} \right\rfloor} & (5)\end{matrix}$

In the above equation (5), └X┘ is the largest integer less than or equalto x.

In a second method, the value N is previously given using a message fromthe upper layer and the value R is calculated using Equation (5).

In a third method, the value R is previously given using a message fromthe upper layer and the vane N is calculated using a value of R*I+J.

Meanwhile, the value K can be calculated using a formula K=N−(R*I+J).

There are several methods for arranging the information on the values I,J, R, N and K, and will be described in the following description.

The N bits are represented by SI₀, SI₁, . . . , SI_(N-1), where SI₀indicates the first bit and SI_(N-1) indicates the N^(th) bit.

$\begin{matrix}{r = \left\lfloor \frac{J}{R} \right\rfloor} & (6)\end{matrix}$where r is an intermediate parameter and may be defined as a quotientobtained by dividing J by R.s=J−r*R  (7)where s is an intermediate parameter, which indicates the remaining bitswhich have failed to be included in R r-bit groups out of J bits. Here,0≦s<R and s is a remainder determined by dividing J by R.

A first embodiment for arranging the information bits is as follows.SI _(1(I+r+1)+i) =d _(i)0≦i≦I−1,1=0,1, . . . ,s−1  (8)SI _(s(I+r+1)+(1−s)*(I+r)+i) =d _(i)0≦i≦I−1,1=s,s+1, . . . ,R−1  (9)

Equations (8) and (9) determine to which position of the CSICH the bitindicating the maximum data rate is to be transmitted.SI _(1(I+r+1)+I+j) =p _(1(r+1)+j)0≦j≦r,1=0,1, . . . ,s−1  (10)SI _(s(I+r+1)+(1−s)(1+r)+I+j) =p _(s(r+1)+(1−s)r+j)0≦j≦r−1,1=s,s+1, . . . ,R−1  (11)

When the SCICH is transmitted as stated above, the information bits aretransmitted in the following order. Thus, the UE is able to know thevalues I, J, R and K from the foregoing description and accordingly,know the bit arrangement.

For example, if I=3, J=16, N=30, R=4 and K=2, the 3 maximum data rateinformation bits, the first 5 bits (1^(st) to 5^(th) bits) of the 16-bitPCPCH use-status information, the 3 maximum data rate information bits,the next 5 bits (6^(th) to 10^(th) bits) of the 16-bit PCPCH use-statusinformation, the 3 maximum data rate information bits, the next 5 bits(11^(th) to 15^(th) bits) of the 16-bit PCPCH use-status information,and the 3 maximum data rate bits are repeatedly arranged in sequence inone frame, and the following 2 bits experience DTX or are padded with‘0’. Here, the 16^(th) bit ‘s’ indicating the last PCPCH use-statusinformation is located at the rear of the first 5 bits (1^(st) to 5^(th)bits) out of the 16 bits. If s=2 bits, it is located at the rear of thenext block (6^(th) to 10^(th) bits).

Equations (10) and (11) determine to which positions of the CSICH thebits indicating the use-status information of the respective PCPCHs usedin the UTRAN are to be transmitted.SI _(R*I+J+k) =e _(k)k=0,1, . . . ,K−1  (12)

Equation (12) determines the positions where the bits remaining aftertransmitting through the CSICH the maximum data rate information bits ofthe PCPCH and the use-status information bits of the respective PCPCHsused in the UTRAN, are to experience zero-padding or DTX.

A second embodiment for arranging the information bits is as follows:t=min [1:1*(r+1)>J]  (13)where t is an intermediate parameter, which corresponds how many timesthe J bits are divided. In Equation (13), t is less than or equal to R.SI _(1(I+r+1)+i) =d _(i)0≦i≦I−1,1=0,1, . . . ,t−1  (14)SI _(J+1*I+i) =d _(i)0≦i≦I−1,1=t,t+1, . . . ,R−1  (15)

Equations (14) and (15) determine to which positions of the CSICH thebits indicating the maximum data rate are to be transmitted.SI _(1(I+r+1)+I+j) =p _(1(r+1)+j)0≦j≦r,1=0,1, . . . ,t−2  (16)SI _((t−1)(I+r+1)+I+j) =p _((t−1)(r+1)+j)0≦j≦r−(t*(r+1)−J)  (17)

Equations (16) and (17) determine to which positions of the CSICH thebits indicating the use-status information of the respective PCPCHs usedin the UTRAN are to be transmitted.SI _(R*I+J+k) =e _(k)k=0,1, . . . ,K−1  (18)

Equation (18) determines the positions where the bits remaining aftertransmitting through the CSICH the maximum data rate information bits ofthe PCPCH and the use-status information bits of the respective PCPCHsused in the UTRAN, are to experience zero-padding or DTX.

A third embodiment for arranging the information bits is as follows.SI_(j)=p_(j)0≦j≦J−1  (19)

Equation (19) determines to which positions of the CSICH the bitsindicating the use-status information of the respective PCPCHs used inthe UTRAN are to be transmitted.SI _(J+1*I+i) =d _(i)0≦i≦I−1,0≦1≦R−1  (20)

Equation (20) determines to which positions of the CSICH the bitsindicating the maximum data rate are to be transmitted.SI _(R*I+J+k) =e _(k)k=0,1, . . . ,K−1  (21)

Equation (21) determines the positions where the bits remaining aftertransmitting through the CSICH the maximum data rate information bits ofthe PCPCH and the use-status information bits of the respective PCPCHsused in the UTRAN, are to experience zero-padding or DTX.

A fourth embodiment for arranging the information bits is as follows.SI _(R*I+j) =p _(j)0≦j≦J−1  (22)

Equation (22) determines to which positions of the CSICH the bitsindicating the use-status information of the respective PCPCHs used inthe UTRAN are to be transmitted.SI _(1*I+i) =d _(i)0≦i≦I−1,0≦1≦R−1  (23)

Equation (23) determines to which positions of the CSICH the bitsindicating the maximum data rate are to be transmitted.SI _(R*I+J+k) =e _(k)k=0,1, . . . ,K−1  (24)

Equation (24) determines the positions where the bits remaining aftertransmitting through the CSICH the maximum data rate information bits ofthe PCPCH and the use-status information bits of the respective PCPCHsused in the UTRAN, are to experience zero-padding or DTX.

A fifth embodiment for arranging the information bits is as follows.

$\begin{matrix}{m = \left\lfloor \frac{K}{R} \right\rfloor} & (25)\end{matrix}$where m is an intermediate parameter.SI _(1(I+r+m)+i) =d _(i)0≦i≦I−1,1=0,1, . . . ,R−1  (26)

Equation (26) determines to which positions of the CSICH the bitsindicating the maximum data rate are to be transmitted.SI _(1(I+r+m)+I+j) =p _(1*r+j)0≦j≦r−1,1=0,1, . . . ,R−2  (27)SI _((R−1)(I+r+m)+I+j) =p _((R−1)r+j)0≦j≦R*I+J−1−(R−1)(I+r+m)−I  (28)

Equations (27) and (28) determine to which positions of the CSICH thebits indicating the use-status information of the respective PCPCHs usedin the UTRAN are to be transmitted.SI _(1*(I+r+m)+I+r+k) =e _(1*m+k)0≦1≦R−2,k=0,1, . . . ,m−1  (29)SI _(R*I+J+k) =e _((R−1)*m+k)k=0,1, . . . ,N−1−R*I−J  (30)

Equations (29) and (30) determine the positions where the bits remainingafter transmitting through the CSICH the maximum data rate informationbits of the PCPCH and the use-status information bits of the respectivePCPCHs used in the UTRAN, are to experience zero-padding or DTX.

In the foregoing embodiments of the method for simultaneouslytransmitting the maximum data rate information available for the PCPCHand the use-status information of the respective PCPCHs used in theUTRAN, it is also possible to transmit a persistence value or an NF_Maxvalue available for the PCPCH in the UTRAN instead of the maximum datarate information.

The transmission method using the separate coding method encodes SI(Status Indicator) information with an error correction code to increasereliability of the SI information transmitted over the CPICH, applies 8coded symbols to an access slot of an access frame, and transmits 120coded symbols per access frame. Here, the number of the SI informationbits, the meaning of the status information and the method fortransmitting the same is previously determined by the UTRAN and the UE,and is also transmitted as a system parameter over the broadcastingchannel (BCH). Therefore, the UE also previously knows the number of theSI information bits and the transmission method, and decodes the CSICHsignal received from the UTRAN.

FIG. 5 shows a structure of a CSICH encoder for transmitting the SIinformation bits according to an embodiment of the present invention.

Referring to FIG. 5, the UTRAN first checks the present use-status ofthe uplink CPCH, i.e., the data rate and channel condition of thechannel presently received over the uplink channel to determine themaximum data rate to be transmitted to the CSICH channel, and thenoutputs corresponding information bits shown in Table 1. The informationbits are the input bits shown in Table 2 below.

A method for coding the input bits may vary according to a transmissionmethod. That is, the coding method may vary according to whether toprovide the channel status information in a frame unit or a slot unit.First, a description will be made of a case where the channel statusinformation is transmitted in a frame unit. The input information (SIbits) and the control information for the number of the SI bits aresimultaneously applied to a repeater 501. The repeater 501 then repeatsthe SI bits according to the control information for the number of theSI bits. However, the control information for the number of the SI bitsis not necessary, when the number of the input information bits ispreviously known to both the UTRAN and the UE.

Operation of the CSICH encoder of FIG. 5 will be described. Upon receiptof 3 SI bits of S0, S1, and S2, the repeater 501 repeats the received SIbits according to the control information indicating that the number ofthe SI bits is 3, and outputs a repeated 60-bit stream of S0, S1, S2,S0, S1, S2, . . . , S0, S1, S2. When repeated 60-bit stream is appliedto an encoder 503 in a 4-bit unit, the encoder 503 encodes the bits inthe bit stream with an (8,4) bi-orthogonal code in a 4-bit unit, andoutputs encoded symbols by 8 symbols. In this manner, when the input60-bit stream is encoded, 120 symbols are output from the encoder 503.By transmitting 8 symbols to every slot in one CSICH, it is possible totransmit the symbols from the encoder 503 over one frame.

Furthermore, when the input information is comprised of 4 bits, the 4input bits are repeated 15 times by the repeater 501 and output as 60symbols. The 60 output symbols are encoded into a bi-orthogonal code of8 symbols in the 4-bit unit by the (8,4) bi-orthogonal encoder 503. Sucha method is equivalent to outputting the input 4 bits into an 8-symbolbi-orthogonal code to transmit the same bi-orthogonal code to every slot(15 slots), with the repeater 501 removed.

Even when the input is 3 bits and an (8,3) encoder is used, the repeater501 is meaningless. Thus, during implementation, it is possible toremove the repeater 501 and transmit the same encoded symbols to everyslot (of 15 slots) by outputting 8 symbols for the 3 input bits.

As described above, if it is possible to transmit the same symbols atevery slot, the UTRAN can transmit the CPCH channel status informationto the UE in a slot unit. That is, the UTRAN determines the maximum datarate at which the UTRAN transmits data to the UE in the slot unit,determines the input bits corresponding to the determined maximum datarate, and transmits the determined input bits in the slot unit. In thiscase, since the UTRAN must analyze the data rate and the status of theuplink channel in the slot unit, it is also possible to transmit themaximum data rate in a unit of several slots.

The (8,4) bi-orthogonal code, which is an error correction code used forencoding, has a relationship between 4 input bits and 8 output symbolsas shown in Table 2 below.

TABLE 2 Input Bits Coded Symbols 0000 0000 0000 0001 0101 0101 0010 00110011 0011 0110 0110 0100 0000 1111 0101 0101 1010 0110 0011 1100 01110110 1001 1000 1111 1111 1001 1010 1010 1010 1100 1100 1011 1001 10011100 1111 0000 1101 1010 0101 1110 1100 0011 1111 1001 0110

FIG. 6 shows a structure of a CSICH decoder corresponding to the CSICHencoder of FIG. 5.

Referring to FIG. 6, 3 input bits are repeated 20 times to create 60bits, and the created 60 bits are applied to the decoder in a unit of 4bits. Assuming that the decoder corresponds to the encoder using the(8,4) bi-orthogonal code. Upon receipt of a received signal by 8symbols, a correlation calculator 601 calculates a correlation betweenthe received signal and the (8,4) bi-orthogonal code, and outputs one of16 correlation values shown in Table 2.

The output correlation value is applied to a likelihood ratio (LLR)value calculator 603, which calculates a ratio of probability P0 toprobability P1, and outputs a 4-bit LLR value. Here, the probability P0indicates a probability that each decoded bit for the 4 information bitstransmitted from the UTRAN according to the control informationdetermined by the number of the SI bits will become 0, and a probabilityP1 indicates a probability that the decoded bit will become 1. The LLRvalue is applied to an LLR value accumulator 605. When 8 symbols arereceived in the next slot, the decoder repeats the above process andadds the 4 bits output from the LLR calculator 603 to the existingvalue. When all the 15 slots are received in the above process, thedecoder determines the status information transmitted from the UTRANusing the value stored in the LLR value accumulator 605.

Next, a description will be made of a case where the input is 4 or 3bits and the (8,4) or (8,3) encoder is used. When a received signal isapplied to the correlation calculator 601 in a unit of 8 symbols, thecorrelation calculator 601 calculates a correlation between the receivedsignal and the (8,4) or (8,3) bi-orthogonal code. If the statusinformation is received from the UTRAN in the slot unit, the decoderdetermines the status information transmitted from the UTRAN using thelargest correlation value according to the correlation. Further, adescription will be made of a case where the UTRAN repeats the samestatus information in the unit of 15 slots (one frame) or several slotsand transmits the repeated status information. When the received signalis applied to the correlation calculator 601 by 8 symbols, thecorrelation calculator 601 calculates a correlation between the receivedsignal and the (8,4) or (8,3) bi-orthogonal code and outputs thecalculated correlation value to the LLR value calculator 603. The LLRvalue calculator 603 then calculates a ratio of a probability P0 to aprobability P1, and outputs an LLR value. Here, the probability P0indicates a probability that a decoded bit for the 4 or 3 informationbits transmitted from the UTRAN will become 0 according to the controlinformation determined depending on the number of the SI bits, and aprobability P1 indicates a probability that the decoded bit willbecome 1. The LLR value is applied to an LLR value accumulator 605 andaccumulated. For the 8 symbols received in the next slot, the decoderrepeats the above process to accumulate the calculated value to theexisting LLR value. Such an operation is performed on every symboltransmitted over one frame. That is, in the case where 8 symbols aretransmitted at one slot, the foregoing operation is repeatedly performed15 times. Therefore, when the UTRAN repeatedly transmits the same statusinformation, the final LLR value accumulated by the foregoing operationwill be equal to the number of the repeated transmissions by the UTRAN.The UE determines the status information transmitted from the UTRANdepending on the accumulated LLR values.

A description will be made of another embodiment which provides higherperformance than the conventional method in terms of a method forencoding the information bits to be transmitted to the CSICH. To bring abetter understanding of this embodiment of the present invention, itwill be assumed that there are 4 information bits to be transmitted tothe CSICH. The information bits will be represented by S0, S1, S2 and S3in sequence. In the prior art, the information bits are simply repeatedbefore transmission. That is, if 120 bits are transmitted in one frame,S0 is repeated 30 times, S1 is repeated 30 times, S2 is repeated 30times and S3 is repeated 30 times. Therefore, the prior art isdisadvantageous in that the UE only receives the necessary CPCHinformation after completely receiving one frame.

To solve this problem, in another embodiment, the sequence oftransmitting the information bits is changed to obtain a time diversityso that the UE can know the CPCH status even though the CPCH of oneframe is not completely received. For example, when the sequence oftransmitting the information bits is S0, S1, S2, S3, S0, S1, S2, S3, S0,S1, S2, S3, . . . , S0, S1, S2 and S3, the same code gain is given in anAWGN (Additive White Gaussian Noise) environment. However, since a gainof the time diversity is given in a fading environment which occursinevitably in the mobile communication system, the invention has ahigher code gain as compared with the prior art. In addition, the UE canknow the status of the CPCH in the UTRAN, even though only one slot ofthe CSICH (when the number of the information bits is 4 and below) isreceived. Even when there are many information bits to be transmitted tothe CSICH, it is possible to know the information about the CPCH in theUTRAN more rapidly as compared with the prior art.

A description will be made below of yet another embodiment whichprovides higher performance than the conventional method in terms of amethod for encoding the information bits to be transmitted to the CSICH.In the foregoing second method, the CSICH information bits weretransmitted in a bit unit. That is, when there are 6 information bits tobe transmitted to the CSICH and the information bits are represented byS0, S1, S2, S3, S4 and S5, the information bits are repeatedlytransmitted in the sequence of S0, S1, S2, S3, S4 and S5. On thecontrary, however, in the third method which will be described below,the information bits are transmitted in a symbol unit.

In the third method, the reason for transmitting the information bits ina symbol unit is because the downlink AICH channel in the current W-CDMAsystem transmits in sequence the information bits to the I channel andthe Q channel. In addition, another reason is to use the same receiveras the AICH receiver, since the current W-CDMA system is so structuredas to repeat the same bit two times in order to transmit the sameinformation bits to the I channel and the Q channel.

A method for transmitting the CSICH information bits in a symbol unitusing the above-stated repeating structure is expressed by Equation (31)below.

$\begin{matrix}{b_{2{({n + {mN}})}} = {b_{{2{({n + {mN}})}} + 1} = \left\{ {\begin{matrix}{{{- 1}\mspace{14mu}{if}},{{SI}_{n} = 1}} \\{{{+ 1}\mspace{14mu}{if}},{{SI}_{n} = 0}}\end{matrix}\left\{ \begin{matrix}{{n = 0},1,\ldots\mspace{14mu},{N - 1}} \\{{m = 0},1,\ldots\mspace{14mu},{\frac{120}{2N} - 1}}\end{matrix} \right.} \right.}} & (31)\end{matrix}$where N is the number of the SI information bits. The current W-CDMAstandard proposes 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30 and 60 for thevalue N. Further, in Equation (31), m indicates a period of the SIinformation bits which are repeatedly transmitted for one CSICH. TheW-CDMA standard proposes 120, 60, 40, 30, 24, 20, 12, 10, 8, 6, 4 and 2for the value m. The value m is determined depending on the value N.Further, in Equation (31), n indicates which one of the N SI informationbits is repeatedly transmitted.

In Equation (31), b_(2(n+mN)) is a 2(n+mN)^(th) information bit and hasthe same value as b_(2(n+mN)+1). That is, the CSICH information bit isrepeated two times with the same value. Meanwhile, in Equation (31),when the value SI_(n) is 1, the information bits are mapped to −1, andwhen the value SI_(n) is 0, the information bits are mapped to +1. Themapping values are interchangeable.

For example, if N=10 in Equation (31), then n has a value of 0 to 9 andm has a value of 0 to 5. Meantime, if SI₀=1, SI₁=0, SI₂=1, SI₃=1, SI₄=0,SI₅=0, SI₆=1, SI₇=1, SI₈=0 and SI₉=1, it is possible to obtain fromEquation (31) the values of b₀=−1, b₁=−1, b₂=1, b₃=1, b₄=−1, b₅=−1,b₆=−1, b₇=−1, b₈=1, b₉=1, b₁₀=1, b₁₁=1, b₁₂=−1, b₁₃=−1, b₁₄=−1, b₁₅=−1,b₁₆=1, b₁₇=1, b₁₈=−1 and b₁₉=−1. These values are repeated 6 timeswithin one CSICH frame. That is, the values are repeated based on b₀=−1,b₂₀=−1, b₄₀=−1, b₆₀=−1, b₈₀=−1 and b₁₀₀=−1.

FIG. 31 shows a CSICH decoder according to another embodiment of thepresent invention.

Referring to FIG. 31, a first repeater 3101 maps input SI informationbits 0 and 1 to +1 and −1, and repeats the mapped SI bits in accordancewith Equation (31). The repeated SI bits are applied to a secondrepeater 3103. The second repeater 3103 repeatedly transmits the outputof the first repeater 3101 according to control information for thenumber of the received SI information bits. The number of repetitions is120/2N. If the first repeater 3101 is removed, FIG. 31 corresponds to ahardware structure for the second embodiment which provides the higherperformance than the prior art in terms of a method for encoding theinformation bits to be transmitted to the CSICH. Otherwise, if the firstand second repeaters 3101 and 3103 are both used, FIG. 31 corresponds toa hardware structure for the third embodiment for encoding theinformation bits to be transmitted to the CSICH.

In the prior art, since the information about the status of each CPCHused in the UTRAN is transmitted over the CSICH, the UTRAN cannottransmit the information in one CSICH slot, but must divide theinformation into the whole slots of one frame before transmission.Therefore, in order to know the CPCH status in the UTRAN, the UE whichdesires to use the CPCH must receive the CSICH for a time much longerthan in this embodiment. In addition, the information about the slotwhere the CSICH information starts and the information about the slotwhere the CSICH information ends is required. However, in thisembodiment of the present invention, when the maximum data ratesupported by the CPCH and the multi-code are used regardless of thenumber of the CPCHs used in the UTRAN, since the number of multi-codeswhich may be used per CPCH is transmitted, the CPCH status informationcan be expressed with 4 bits regardless of the number of the CPCHs. InFIGS. 5 and 6, although one information bit is used for the case wherethe multi-code is used, it is possible to allocate the information bitfor the number, NFM (Number of Frame Max (NF_MAX)), of frames which canmaximally transmit the CPCH message. The UTRAN can set one NFM per CPCH.Alternatively, the NFM can correspond to the CA or correspond to thedownlink DPCCH. In order to select the NFM, the UE may match NFM withthe AP or to the AP sub-channel. There are several methods for settingand informing the NF_MAX in the UTRAN and the UE. As one method, theUTRAN may set either one NF_MAX per CPCH set or several NF_MAXs per CPCHset. When UTRAN sets several NF_MAXs per CPCH set, the UE may personallyselect each NF_MAX in combination of the AP signature and the APsub-channel which are transmitted to the UTRAN.

In another method for setting NF_MAX, the UTRAN matches the NF_MAX tothe channel allocation message and personally provides the UE with theinformation on the NF_MAX. In yet another method for setting NF_MAX, itis possible to match to NF_MAX to the uplink CPCH and its correspondingdownlink DPCCH. In still another method, a supervision may be usedwithout the NFM. That is, when there is no data to transmit, the UEstops transmission, and upon detecting this, the UTRAN releases thechannel. In still another method, the NFM can be transmitted to the UEusing the downlink DPDCH.

AP/AP_AICH

Upon receiving the information about the CPCH in the UTRAN through theCSICH of FIG. 4, the UE prepares to transmit the AP 333 of FIG. 3 inorder to obtain the information about the right to use the CPCH channeland the use of the CPCH channel.

To transmit the AP 333, the UE should select a signature for the AP. Inthe preferred embodiments of the present invention, it is possible toselect a proper access service class (ASC) based on the informationabout the CPCH in the UTRAN, acquired through the CSICH before selectingthe signature, and the property of the data that the UE will transmitover the CPCH. For example, the ASC can be distinguished according to adesired class of the UE, the data rate used by the UE, or the servicetype used by the UE. The ASC is transmitted to the UEs in the UTRAN overthe broadcasting channel, and the UE selects a proper ASC according tothe CSICH and the property of the data to be transmitted. Upon selectingthe ASC, the UE randomly selects one of AP sub-channel groups for theCPCH, defined in the ASC. If the system frame number (SFN) presentlytransmitted from the UTRAN is defined as K using Table 3 below and theSFN used for the frame transmitted from the UTRAN, the UE draws theaccess slots which are available at (K+1) and (K+2)^(th) frames andselects one of the drawn access slots to transmit the AP 331 of FIG. 3.The “AP sub-channel group” refers to the 12 sub-channel groups shown inTable 3.

TABLE 3 Sub-channel Number SFN mod 8 0 1 2 3 4 5 6 7 8 9 10 11 0 0 1 2 34 5 6 7 1 8 9 10 11 2 12 13 14 3 0 1 2 3 4 5 6 7 4 9 10 11 12 13 14 8 56 7 0 1 2 3 4 5 6 3 4 5 6 7 7 8 9 10 11 12 13 14

A structure of an access slot used to transmit the AP 331 of FIG. 3 isshown in FIG. 7. Reference numeral 701 indicates an access slot, whichhas a length of 5120 chips. The access slot has a structure in which theaccess slot number is repeated from 0 to 14, and has a repetition periodof 20 ms. Reference numeral 703 indicates a beginning and an end of the0^(th) to 14^(th) access slots.

Referring to FIG. 7, since SFN has a unit of 10 ms, a beginning of the0^(th) access slot is identical to a beginning of a frame whose SFN isan even number, and an end of the 14^(th) access slot is identical to anend of a frame whose SFN is an odd number.

The UE randomly selects one of the valid signatures and a signatureselected by the UE in the above described manner, i.e., the sub-channelgroups for the CPCH, defined in the ASC allocated by the UTRAN. The UEassembles the AP 331 using the selected signature and transmits theassembled AP to the UTRAN in sync with the timing of the UTRAN. The AP331 is distinguished according to the AP signature used for the AP, andeach signature is mapped to the maximum data rate, or the maximum datarate and the NFM can be mapped. Therefore, the information indicated bythe AP is the information about the maximum data rate of a CPCH to beused by the UE or the number of data frames to be transmitted by the UE,or a combination of the two kinds of the above information. Although thecombination of the maximum data rate for the AP and the number of thedata frames to be transmitted by the CPCH may be mapped, it is alsopossible, as an alternative method, to select the maximum data rate andNF_MAX (Number of Frame Max) by combining the AP signature with anaccess slot for transmitting an AP made by the UE using the APsignature, and transmit them to the UTRAN. As an example of the abovemethod, the AP signature selected by the UE can be associated with themaximum data rate or the spreading factor of the data to be transmittedby the UE over the CPCH and the access sub-channel for transmitting theAP made by the UE using the above signature can be associated with theNF_MAX, and vice versa.

For example and referring to FIG. 3, in the process for transmitting theAP from the UE to the UTRAN, after transmitting the AP 333, the UEawaits receipt of the AP_AICH signal from the UTRAN for a predeterminedtime (τ_(p-p)) 332 (i.e., 3 or 4-slot time), and upon receipt of theAP_AICH signal, determines whether the AP_AICH signal includes aresponse to the AP signature transmitted by the UE. If the AP_AICHsignal is not received within the time 332 or the AP_AICH signal is aNAK signal, the UE increases transmission power of the AP, and transmitsAP 335 to the UTRAN at the increased transmission power. When the UTRANreceives AP 335 and it is possible to allocate the CPCH having a datarate requested by the UE, the UTRAN transmits the AP_AICH 303 inresponse to the received AP 335 after a lapse of a previously appointedtime (τ_(p-AI)) 302. In this case, if the uplink capacity of the UTRANexceeds a predetermined value or there is no more demodulation, theUTRAN transmits a NAK signal to temporarily discontinue UE'stransmitting on the uplink common channel. In addition, when the UTRANfails to detect the AP, the UTRAN cannot send the ACK or NAK signal onthe AICH such as the AP_AICH 303. Therefore, in the embodiment, it willbe assumed that nothing is transmitted.

CD

Upon receipt of the ACK signal over the AP_AICH 303, the UE transmitsthe CD_P 337. The CD_P has the same structure as that of the AP, and thesignature used to construct the CD_P can be selected from the samesignature group as the signature group used for the AP. When a signaturefor the CD_P is used out of the group of the signatures identical to theAP, different scrambling codes are used for the AP and the CD_P in orderto distinguish between the AP and the CD_P. The scrambling codes havethe same initial value but may have different start points.Alternatively, the scrambling codes for the AP and the CD_P may havedifferent initial values. The reason for selecting a given signature andtransmitting the CD_P is to decrease the probability that the same CD_Pmay be selected even though there occurs a collision because two or moreUEs simultaneously transmit the AP. In the prior art, one CD_P istransmitted at a given transmission time to decrease the probability ofan uplink collision between the different UEs. However, in such amethod, if another user requests the UTRAN for the right to use the CPCHusing the same CD_P before processing a response to the CD_P from oneUE, the UTRAN cannot respond to the UE which transmitted the later CD_P.Even if the UTRAN responds to this later UE, there is a probability ofan uplink collision with the UE which first transmitted the CD_P.

In FIG. 3, the UTRAN transmits CD/CA_ICH 305 in response to the CD_P 337transmitted from the UE. The CD_ICH out of the CD/CA_ICH will be firstdescribed. The CD_ICH is a channel for transmitting the ACK signal forthe CD_P to the corresponding UE, when the UE transmits the signatureused for the CD_P over the downlink. The CD_ICH can be spread using adifferent orthogonal channelization code from that of the AP_AICH.Therefore, the CD_ICH and the AP_AICH can be transmitted over differentphysical channels, or can be transmitted over the same physical channelby time dividing one orthogonal channel. In the preferred embodiments ofthe present invention, the CD_ICH is transmitted over a differentphysical channel from that of the AP_AICH. That is, the CD_ICH and theAP_AICH are spread with an orthogonal spreading code of length 256 andtransmitted over independent physical channels.

CA

In FIG. 3, the CA_ICH (Channel Allocation_Indicator Channel) includeschannel information of the CPCH allocated to the UE by the UTRAN anddownlink channel allocation information for allocating power control ofthe CPCH. The downlink allocated to power control the CPCH is availablein several methods.

First, a downlink shared power control channel is used. A method forcontrolling transmission power of a channel using the shared powercontrol channel is disclosed in detail in Korean patent application No.1998-10394, the contents of which are hereby incorporated by reference.Further, it is possible to transmit a power control command for the CPCHby using the shared power control channel. Allocating the downlinkchannel may include information about the channel number and the timeslot for the downlink shared power control used for power control.

Second, a downlink control channel can be used which is time-dividedinto a message and a power control command. In the W-CDMA system, thischannel is defined to control the downlink shared channel. Even when thedata and the power control command is time divided for transmission, thechannel information includes the information about the channel numberand the time slot of the downlink control channel.

Third, one downlink channel can be allocated to control the CPCH. Thepower control command and the control command can be transmittedtogether over this channel. In this case, the channel informationbecomes a channel number of the downlink channel.

In the preferred embodiments of the present invention, it is assumedthat the CD/CA_ICH are simultaneously transmitted. However, the CA_ICHmay be transmitted after transmission of the CD_ICH, or theCD_ICH/CA_ICH may be simultaneously transmitted. When the CD_ICH/CA_ICHare simultaneously transmitted, they may be transmitted with either thedifferent channelization codes or the same channelization code. Further,it will be assumed that in order to decrease the delay in processing amessage from a upper layer, a channel allocation command transmittedover the CA_ICH is transmitted in the same format as the CD_ICH. In thiscase, if there exist 16 signatures and 16 CPCHs, each CPCH willcorrespond to a unique one of the signatures. For example, when theUTRAN desires to allocate a 5^(th) CPCH for transmitting a message tothe UE, the UTRAN transmits a 5^(th) signature corresponding to the5^(th) CPCH in the channel allocation command.

If it is assumed that the CA_ICH frame over which the channel allocationcommand is transmitted has a length of 20 ms and includes 15 slots, thisstructure will be identical to the structure of the AP_AICH and theCD_ICH. The frame for transmitting AP_AICH and the CD_ICH is comprisedof 15 slots and each slot can be comprised of 20 symbols. It will beassumed that one symbol period (or duration) has a length of 256 chipsand a part where responses to the AP, CD and CA are transmitted, istransmitted in only a 16-symbol period.

Therefore, the channel allocation command transmitted as shown in FIG. 3can be comprised of 16 symbols, and each symbol has a length of 256chips. Further, each symbol is multiplied by the 1-bit signature and thespreading code and then transmitted over the downlink, and an orthogonalproperty (or orthogonality) is guaranteed between the signatures.

In the preferred embodiments of the present invention, the CA_ICH istransmitted using 1, 2 or 4 signatures for the channel allocationcommand.

In FIG. 3, upon receipt of the CD/CA_ICH 305 transmitted from the UTRAN,the UE examines whether the CD_ICH includes an ACK signal, and analyzesinformation about the use of the CPCH channel, transmitted over theCA_ICH. Analysis of the two kinds of the above information can be madeeither sequentially or simultaneously. Receiving the ACK signal throughthe CD_ICH out of the received CD/CA_ICH 305 and the channel allocationinformation through the CA_ICH, the UE assembles the data part 343 andthe control part 341 of the CPCH according to the channel information ofthe CPCH allocated by the UTRAN, as shown in FIG. 3. Further, beforetransmitting the data part 343 and the control part 341 of the CPCH, theUE transmits the power control preamble (PC_P) 339 to the UTRAN after alapse of a predetermined time (τ_(CD) _(—) _(p-PC) _(—) _(p)) 336 from atime when the CD/CA_ICH, set before the CPCH setting process, arereceived.

PC_P

Although the power control preamble PC_P has a length of 0 or 8 slots,it will be assumed in the preferred embodiments of the present inventionthat the power control preamble PC_P 339 transmits 8 slots. The primarypurpose of the power control preamble PC_P is to enable the UTRAN toinitially set an uplink transmission power of the UE using a pilot fieldof the power control preamble. However, in this embodiment of thepresent invention, as another use, the power control preamble can beused to reconfirm the channel allocation message received at the UE. Areason for reconfirming the channel allocation message is to prevent acollision with a CPCH used by another UE, which may be caused by theUE's improperly setting the CPCH because the CA_ICH received at the UEhas an error. When the power control preamble is used for the purpose ofreconfirming the channel allocation message, the power control preamblehas a length of 8 slots.

Although the CA message reconfirming method is used for the powercontrol preamble, the UTRAN has no difficulty in measuring the power andconfirming the CA message since it already knows a pattern of the pilotbit used for the power control preamble.

At a time close to the time when the power control preamble 339 istransmitted, the UTRAN starts transmitting the downlink dedicationchannel for uplink power control of the CPCH for the corresponding UE. Achannelization code for the downlink dedicated channel is transmitted tothe UE through the CA message, and the downlink dedicated channel iscomprised of a pilot field, a power control command field and a messagefield. The message field is transmitted only when the UTRAN has data totransmit to the UE. Reference numeral 307 of FIG. 3 indicates an uplinkpower control command field, and reference numeral 309 indicates a pilotfield.

For the case where the power control preamble 339 of FIG. 3 is used notonly for power control but also for reconfirming the CA (ChannelAllocation) message, if the CA message transmitted to the analyzed powercontrol preamble by the UTRAN is different from the message transmittedto the CD/CA_ICH 305 by the UTRAN, the UTRAN continuously transmits atransmission power-decreasing command to the power control field of theestablished downlink dedicated channel, and transmits a CPCHtransmission stop message to the FACH or the established downlinkdedicated channel.

After transmitting the power control preamble 339 of FIG. 3, the UEimmediately transmits the CPCH message part 343. Upon receipt of theCPCH transmission stop command from the UTRAN during transmission of theCPCH message part, the UE immediately stops transmission of the CPCH. Ifthe CPCH transmission stop command is not received, the UE receives anACK or NAK for the CPCH from the UTRAN after completing transmission ofthe CPCH.

Structure of the Scrambling Code

FIG. 8A shows a structure of an uplink scrambling code used in the priorart, and FIG. 8B shows a structure of an uplink scrambling code used inan embodiment of the present invention.

More specifically, FIG. 8A shows a structure of an uplink scramblingcode used in the process of initially establishing and transmitting theCPCH in the prior art. Reference numeral 801 indicates an uplinkscrambling code used for the AP, and reference numeral 803 indicates anuplink scrambling code used for the CD_P. The uplink scrambling codeused for the AP and the uplink scrambling code used for the CD_P are theuplink scrambling codes generated from the same initial value: 0^(th) to4095^(th) values are used in the AP part, and 4096^(th) to 8191^(st)values are used in the CD_P part. For the uplink scrambling codes forthe AP and the CD_P, the uplink scrambling codes can be used which arebroadcast by the UTRAN or previously set in the system. In addition, forthe uplink scrambling code, a sequence of length 256 can be used, and along code which is not repeated for the AP or CD_P period can also beused. In the AP and the CD_P of FIG. 8A, the same uplink scrambling codecan be used. That is, the AP and the CD_P can be used equally by using aspecific part of the uplink scrambling code generated using the sameinitial value. In this case, the signature used for the AP and thesignature used for the CD_P are selected from the different signaturegroups. In such an example, 8 of 16 signatures used for a given accesschannel are allocated for the AP and the remaining 8 signatures areallocated for the CD_P.

Reference numerals 805 and 807 of FIG. 8A indicate uplink scramblingcodes used for the power control preamble PC_P and the CPCH messagepart, respectively. The parts used in the uplink scrambling codes havingthe same initial value are made different to be used for the PC_P andthe CPCH message part. The uplink scrambling code used for the PC_P partand the CPCH message part can be the same scrambling code as the uplinkscrambling code used for the AP and the CD_P, or can be the uplinkscrambling code corresponding on a one-to-one basis to the signature forthe AP transmitted by the UE. A PC_P scrambling code 805 of FIG. 8A uses0^(th) to 20,479^(th) values of the uplink scrambling code #B, and amessage scrambling code 807 uses a scrambling code of length 38,400 byusing 20,480^(th) to 58,888^(th) values of the uplink scrambling code.Also, for the scrambling codes used for the PC_P and the CPCH messagepart, a scrambling code having a length of 256 can be used.

FIG. 8B shows a structure of an uplink scrambling code used in anembodiment of the present invention. Reference numerals 811 and 813indicate uplink scrambling codes used for the AP and the CD_Prespectively. The uplink scrambling codes 811 and 813 are used in thesame manner as in the prior art. The uplink scrambling codes are knownto the UE by the UTRAN, or the uplink scrambling codes are previouslyappointed in the system.

Reference numeral 815 of FIG. 8B indicates an uplink scrambling codeused for the PC_P part. The uplink scrambling code used for the PC_Ppart may be the same scrambling code as the uplink scrambling code usedfor the AP and the CD_P, or can be the scrambling code which correspondsto the signature used for the AP on a one-to-one basis. Referencenumeral 815 of FIG. 8B indicates a scrambling code used for the PC_Ppart, having 0^(th) to 20,479^(th) values. Reference numeral 817 of FIG.8B indicates an uplink scrambling code used for the CPCH message part.For this scrambling code, there can be used the same code as thescrambling code used for the PC_P, or a scrambling code whichcorresponds to the scrambling code used for the PC_P or the signatureused for the AP on a one-to-one basis. The CPCH message part usesscrambling codes of length 38,400 of 0^(th) to 38,399^(th).

For all the scrambling codes used in describing the structure of thescrambling code according to an embodiment of the present invention, thelong scrambling code is used which is not repeated for the AP, CD_P,PC_P and the CPCH message part. However, it is also possible to use ashort scrambling code having a length of 256.

Detailed Description of the AP

FIGS. 9A and 9B show a channel structure of the CPCH access preambleaccording to an embodiment of the present invention and a scheme forgenerating the same, respectively. More specifically, FIG. 9A shows thechannel structure of the AP, and FIG. 9B shows a scheme for generatingone AP slot.

Reference numeral 901 of FIG. 9A indicates a length of the accesspreamble AP, the size of which is identical to 256 times the length of asignature 903 for the AP. The signature 903 for the AP is an orthogonalcode of length 16. A variable ‘K’ indicated in the signature 903 of FIG.9A can be 0 to 15. That is, in this embodiment of the present invention,there are provided 16 kinds of the signatures. Table 4 below shows thesignatures for the AP, by way of example. A method for selecting thesignature 903 in the UE is as follows. That is, the UE first determinesthe maximum data rate which can be supported by the CPCH in the UTRANthrough the CSICH transmitted by the UTRAN and the number of themulti-codes which can be used in one CPCH, and selects a proper ASC inconsideration of the properties, data rate and transmission length ofthe data to be transmitted through the CPCH. Thereafter, the UE selectsa signature proper for the UE data traffic out of the signatures definedin the selected ASC.

TABLE 4 n Signature 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 P₀(n) A A A AA A A A A A A A A A A A P₁(n) A −A A −A A −A A −A A −A A −A A −A A −AP₂(n) A A −A −A A A −A −A A A −A −A A A −A −A P₃(n) A −A −A A A −A −A AA −A −A A A −A −A A P₄(n) A A A A −A −A −A −A A A A A −A −A −A −A P₅(n)A −A A −A −A A −A A A −A A −A −A A −A A P₆(n) A A −A A −A −A A A A A −AA −A −A A A P₇(n) A −A −A A −A A A −A A −A −A A −A A A −A P₈(n) A A A AA A A A −A −A −A −A −A −A −A −A P₉(n) A −A A −A A −A A −A −A A −A A −A A−A A  P₁₀(n) A A −A −A A A −A −A −A −A A A −A −A A A  P₁₁(n) A −A −A A A−A −A A −A A A −A −A A A −A  P₁₂(n) A A A A −A −A −A −A −A −A −A −A A AA A  P₁₃(n) A −A A −A −A A −A A −A A −A A A −A A −A  P₁₄(n) A A −A A −A−A A A −A −A A −A A A −A −A  P₁₅(n) A −A −A A −A A A −A −A A A −A A −A−A A

An access preamble 905 of FIG. 9B has a size indicated by 901. Theaccess preamble 905 is spread with an uplink scrambling code 907 by amultiplier 906 and transmitted to the UTRAN. The time point where the APis transmitted has been described with reference to FIG. 7 and Table 3,and the scrambling code 907 has been described with reference to FIG.8B.

The information transmitted from the UE to the UTRAN through the AP ofFIG. 9B includes the data rate of the CPCH, requested by the UE, or thenumber of frames to be transmitted by the UE, or includes informationgenerated by associating a combination of the two kinds of the aboveinformation with the signature on a one-to-one basis.

In the prior art, with regard to the information transmitted from the UEto the UTRAN through the AP, the UE determines the uplink scramblingcode and data rate necessary for the CPCH, the channelization code anddata rate for the downlink dedicated channel for CPCH power control, andthe number of data frames to be transmitted, and transmits thecorresponding signature to the UTRAN through the AP. When theinformation transmitted through the AP is determined in the abovemanner, the UTRAN has only the function of allowing or not allowing theUE to use the channel requested by the UE. Therefore, even though thereexists an available CPCH in the UTRAN, the prior art cannot allocate theCPCH to the UE. When there are many UEs which requests the CPCH havingthe same condition, a collision occurs between the different UEs tryingto acquire the CPCH, thus increasing the time required when the UEacquires the channel. In this embodiment of the present invention,however, the UE transmits only the possible maximum data rate of theCPCH, or the maximum data rate and the number of the data frames to betransmitted to the UTRAN, and the UTRAN then determines, through the CA,the other information for using the CPCH of the uplink scrambling codeand the channelization code for the downlink dedicated channel.Therefore, in the embodiment of the present invention, it is possible toendow the UE with the right to use the CPCH, thereby making it possibleto efficiently and flexibly allocate the CPCH in the UTRAN.

When the UTRAN supports multi-channel code transmission which usesmultiple channelization codes in one PCPCH (Physical CPCH), the APsignature used for transmission of the AP may indicate either ascrambling code used for transmission of the multi-codes or the numberof the multiple codes desired by the UE when the UE can select thenumber of the multiple codes to be used in the PCPCH. When the APsignature indicates the uplink scrambling code for the multiple codes,the channel allocation message transmitted to the UE by the UTRAN mayindicate the number of the multiple codes to be used by the UE, and whenthe AP signature indicates the number of the multiple codes that the UEdesires to use, the channel allocation message may indicate the uplinkscrambling code to be used by the UE in transmitting the multiple codes.

Detailed Description of the CD_P

FIGS. 10A and 10B show the channel structure of the collision detectionpreamble CD_P and a scheme for generating the same, respectively,according to an embodiment of the present invention. The structure ofthe CD_P and its generating scheme are the same as those of the AP shownin FIGS. 9A and 9B. The uplink scrambling code shown in FIG. 10B isdifferent from the AP scrambling code shown in FIG. 8B. Referencenumeral 1001 of FIG. 10A indicates a length of the CD_P, which is 256times a signature 1003 for the AP, shown in Table 4. A variable ‘j’ ofthe signature 1003 can be 0 to 15. That is, there are provided 16signatures for the CD_P. The signature 1003 of FIG. 10A is randomlyselected from the 16 signatures. One reason for randomly selecting thesignature is to prevent a collision between the UEs which have receivedthe ACK signal after transmitting the same AP to the UTRAN, therebyhaving to perform the confirmation process again. In using the signature1003 of FIG. 10A, the prior art uses a method which is used whenspecifying only one signature for the CD_P or transmitting the AP in agiven access channel. The conventional method for transmitting the CD_Pusing only one signature has an object of preventing a collision betweenthe UEs by randomizing the transmission time point of the CD_P insteadof using the same signature. However, the conventional method isdisadvantageous in that if another UE transmits the CD_P to the UTRAN ata time point where the UTRAN has not transmitted an ACK for the receivedCD_P received from one UE, the UTRAN cannot process the CD_P transmittedfrom another UE before processing the ACK for the first received CD_P.That is, the UTRAN cannot process the CD_P from the other UEs whileprocessing the CD_P from one UE. The conventional method fortransmitting the CD_P in the random access channel RACH isdisadvantageous in that it takes a long time until the UE detects anaccess slot for transmitting the CD_P, causing an increased time delayin transmitting the CD_P.

In an embodiment of the present invention, upon receipt of the AP_AICH,the UE selects a given signature after a lapse of a predetermined timeand transmits the selected signature to the UTRAN.

The CD_P 1005 of FIG. 10B has a same size indicated by 1001 of FIG. 10A.The CD_P 1005 is spread with the uplink scrambling code 1007 by amultiplier 1006 and then transmitted to the UTRAN after a lapse of apredetermined time from the time point where the AP_AICH is received. InFIG. 10B, for the uplink scrambling code, the code (of the 0^(th) to4,095^(th) chips) which is identical to that used for the AP can beused. That is, when 12 of the 16 signatures are used for the preamble ofthe random access channel (RACH), the remaining 4 signatures can bedividedly used for the AP and the CD_P of the CPCH. The uplinkscrambling code 1007 has been described with reference to FIG. 8B.

AP_AICH and CD/CA_ICH

FIG. 11A shows a channel structure of an access preamble acquisitionindicator channel (AP_AICH) over which the UTRAN can transmit ACK or NAKin response to the received AP, a collision detection indicator channel(CD_ICH) over which the UTRAN can transmit ACK or NAK in response to thereceived CD_P, or a channel allocation indicator channel (CA_ICH) overwhich the UTRAN transmits a CPCH channel allocation command to the UE,and FIG. 11B shows a scheme for generating the same.

Reference numeral 1101 of FIG. 11A indicates an AP_AICH indicator partfor transmitting ACK and NAK for the AP acquired by the UTRAN. Whentransmitting the AP_AICH, a rear part 1105 of the indicator part (orsignature transmission part) 1101 transmits the CSICH signal. Inaddition, FIG. 11A shows a structure for transmitting the CD/CA_ICHsignal for transmitting a response to the CD_P signal, and the channelallocation signal. However, the indicator part 1101 has the same channelstructure as the AP_AICH, and the response signals (ACK, NAK orAcquisition_Fail) for the CP_D and the CA signal are simultaneouslytransmitted. In describing the CD/CA_ICH of FIG. 11A, the rear part 1105of the indicator part 1101 may either be left empty or transmit theCSICH. The AP_AICH and the CD/CA_ICH can be distinguished from eachother by making the channelization codes (OVSF codes) become differentusing the same scrambling code. The channel structure of the CSICH andits generating scheme have been described with reference to FIGS. 4A and4B. Reference numeral 1111 of FIG. 11B indicates a frame structure of anindicator channel (ICH). As illustrated, one ICH frame has a length of20 ms, and is comprised of 15 slots, each of which can transmit 0 ormore than 1 of the 16 signatures shown in Table 4. A CPCH statusindicator channel (CSICH) 1107 of FIG. 11B has the same size asrepresented by 1103 of FIG. 11A. Reference numeral 1109 of FIG. 11Bindicates a channelization code, for which the AP_AICH, CD_ICH, andCA_ICH may use different channelization codes and the CD_ICH and CA_ICHmay use the same channelization code. A signal on the CPCH statusindicator channel 1107 is spread with the channelization code 1109 by amultiplier 1108. The 15 spread slots constituting one ICH frame arespread with a downlink scrambling code 1113 by a multiplier 1112 beforetransmission.

FIG. 12 shows an ICH generator for generating CD_ICH and CA_ICHcommands. An AP_AICH generator also has the same structure. As describedabove, to each slot of the ICH frame is allocated a corresponding one ofthe 16 signatures. Referring to FIG. 12, multipliers 1201–1216 receivecorresponding signatures (orthogonal codes W₁–W₁₆) as a first input andreceive acquisition indicators AI₁–AI₁₆ as a second input, respectively.Each AI has a value of 1, 0 or −1 for the AP_AICH and the CD_ICH: AI=1indicates ACK, AI=−1 indicates NAK, and AI=0 indicates a failure toacquire the corresponding signature transmitted from the UE. Therefore,the multipliers 1201–1216 multiply the corresponding orthogonal code bythe corresponding acquisition indicator AI, respectively, and a summer1220 sums up the outputs of the multipliers 1201–1216 and outputs theresulting value as an ICH signal.

The UTRAN can transmit the channel allocation command using the ICHgenerator of FIG. 12 in several methods which are given below by way ofexample.

1. First Channel Allocation Method

In this method, one downlink channel is allocated to transmit thechannel allocation command over the allocated channel. FIGS. 13A and 13Bshow the structures of the CD_ICH and the CA_ICH implemented accordingto the first method. More specifically, FIG. 13A shows the slotstructure of the CD_ICH and the CA_ICH, and FIG. 13B shows an exemplarymethod for transmitting the CD_ICH and CA_ICH. Reference numeral 1301 ofFIG. 13A indicates a transmission slot structure of the CD_ICH fortransmitting a response signal for the CD_P. Reference numeral 1311indicates a transmission slot structure of the CA_ICH for transmitting achannel allocation command. Reference numeral 1331 indicates atransmission frame structure of the CD_ICH for transmitting a responsesignal for the CD_P. Reference numeral 1341 indicates a frame structurefor transmitting the channel allocation command over the CA_ICH with atune delay τ after transmission of the CD_ICH frame. Reference numerals1303 and 1313 indicate the CSICH part. The method for allocating thechannels as shown in FIGS. 13A and 13B has the following advantages. Inthis channel allocation method, the CD_ICH and the CA_ICH are physicallyseparated, because they have different downlink channels. Therefore, ifthe AICH has 16 signatures, the first channel allocation method can use16 signatures for the CD_ICH and also use 16 signatures for the CA_ICH.In this case, the kinds of information which can be transmitted usingthe sign of the signatures can be doubled. Therefore, by using the signof ‘+1’ or ‘−1’ of the CA_ICH, it is possible to use 32 signatures forthe CA_ICH.

In this case, it is possible to allocate the different channels toseveral users, who have simultaneously requested the same kind ofchannel, in the following sequence. First, it is assumed that UE#1, UE#2and UE#3 in a UTRAN simultaneously transmit AP#3 to the UTRAN to requesta channel corresponding to the AP#3, and UE#4 transmits AP#5 to theUTRAN to request a channel corresponding to the AP#5. This assumptioncorresponds to the first column of Table 5 below. In this case, theUTRAN recognizes the AP#3 and the AP#5. At this point, the UTRANgenerates AP_AICH as a response to the received APs according to adefined previously criterion. As an example of the previously definedcriterion, the UTRAN can respond to the received APs according to areceiving power ratio of the APs. Here, it is assumed that the UTRANselects the AP#3. The UTRAN then transmits ACK to the AP#3 and NAK tothe AP#5. This corresponds to the second column of Table 5.

Then, the UE#1, UE#2 and UE#3 receive ACK transmitted from the UTRAN,and randomly generate CD_Ps, respectively. When three UEs generate theCD_Ps (i.e., at least two UEs generate the CD_Ps for one AP_AICH), therespective UEs generate the CD_Ps using given signatures and the CD_Pstransmitted to the UTRAN have the different signatures. Herein, it isassumed that the UE#1 generated CD_P#6, the UE#2 generated CD_P#2 andthe UE#3 generated CD_P#9, respectively. Upon receipt of the CD_Pstransmitted from the UEs, the UTRAN recognizes receipt of the 3 CD Psand examines whether the CPCHs requested by the UEs are available. Whenthere exist more than 3 CPCHs in the UTRAN, requested by the UEs, theUTRAN transmits ACKs to CD_ICH#2, CD_ICH#6 and CD_ICH#9, and transmitsthree channel allocation messages through the CA_ICH. In this case, ifthe UTRAN transmits the messages for allocating the channel numbers of#4, #6 and #10 through the CA_ICH, the UEs will know the CPCH numberallocated to themselves in the following process. The UE#1 knows thesignature for the CD_P transmitted to the UTRAN and also knows that thesignature number is 6. In this manner, even when the UTRAN transmitsseveral ACKs to the CD_ICH, it is possible to know how many ACKs havebeen transmitted.

A description of this embodiment of the present invention has been madeon the assumption of the case shown in Table 5. First, the UTRAN hastransmitted three ACKs to the UEs through CD_ICH, and also transmittedthree channel allocation messages to the CA_ICH. The transmitted channelallocation messages correspond to the channel numbers of #2, #6 and #9.Upon receipt of the CD_ICH and the CA_ICH, the UE#1 may know that threeUEs in the UTRAN have simultaneously requested the CPCH channels and theUE#1 itself can use the CPCH according to the contents of the secondmessage out of the channel allocation messages transmitted through theCA_ICH, in the sequence of the ACKs of the CD_ICH.

TABLE 5 UE No AP No AP_IACH CD_P No CA_ICH 1 3 ACK#3 6 (Second) #6(Second) 2 3 ACK#3 2 (First) #4 (First) 3 3 ACK#3 9 (Third) #10 (Third)4 5 NAK#5

In this process, since the UE#2 has transmitted the CD_P#2, the UE#2will use the fourth one out of the channel allocation messagestransmitted by the CA_ICH. In the same manner, the UE#3 is allocated the10^(th) channel. In this manner, it is possible to simultaneouslyallocate several channel to several users.

2. Second Channel Allocation Method

The second channel allocation method is a modified form of the firstchannel allocation method, implemented by setting a transmission timedifference τ between the CD_ICH frame and the CA_ICH frame to ‘0’ tosimultaneously transmit the CD_ICH and the CA_ICH. The W-CDMA systemspreads one symbol of the AP_AICH with a spreading factor 256 andtransmits 16 symbols at one slot of the AICH. The method forsimultaneously transmitting the CD_ICH and the CA_ICH can be implementedby using symbols of different lengths. That is, the method can beimplemented by allocating orthogonal codes having different spreadingfactors to the CD_ICH and the CA_ICH. As an example of the secondmethod, when the possible number of the signatures used for the CD_P is16 and a maximum of 16 CPCHs can be allocated, it is possible toallocate the channels of a length of 512 chips to the CA_ICH and theCD_ICH, and the CA_ICH and the CD_ICH each can transmit 8 symbols with alength of 512 chips. Here, by allocating 8 signatures, being orthogonalto one another, to the CD_ICH and the CA_ICH and multiplying theallocated 8 signatures by a sign of +1/−1, it is possible to transmit 16kinds of the CA_ICH and the CD_ICH. This method is advantageous in thatit is not necessary to allocate separate orthogonal codes to the CA_ICH.

As described above, the orthogonal codes having a length of 512 chipscan be allocated to the CA_ICH and the CD_ICH in the following method.One orthogonal code W1 of length 256 is allocated to both the CA_ICH andthe CD_ICH. For the orthogonal code of length 512 allocated to theCD_ICH, the orthogonal code W_(i) is repeated twice to create anorthogonal code [W_(i) W_(i)] of length 512. Further, for the orthogonalcode of length 512 allocated to the CA_ICH, an inverse orthogonal code−W_(i) is connected to the orthogonal code W_(i) to create an orthogonalcode [W_(i)−W_(i)]. It is possible to simultaneously transmit the CD_ICHand the CA_ICH without allocating separate orthogonal codes, by usingthe created orthogonal codes [W_(i) W_(i)] and [W_(i)−W_(i)].

FIG. 14 shows another example of the second method, wherein the CD_ICHand the CA_ICH are simultaneously transmitted by allocating differentchannelization codes having the same spreading factor to them. Referencenumerals 1401 and 1411 of FIG. 14 indicate the CD_ICH part and theCA_ICH part, respectively. Reference numerals 1403 and 1413 indicatedifferent orthogonal channelization codes having the same spreadingfactor of 256. Reference numerals 1405 and 1415 indicate a CD_ICH frameand a CA_ICH frame each comprised of 15 access slots having a length of5120 chips.

Referring to FIG. 14, the CD_ICH part 1401 is created by multiplying thesignatures obtained by repeating a signature of length 16 twice in asymbol unit by sign values of ‘1’, ‘−1’ or ‘0’ (indicating ACK, NAK, orAcquisition_Fail, respectively) on a symbol unit basis. The CD_ICH part1401 can simultaneously transmit ACK and NAK for several signatures. TheCD_ICH part 1401 is spread with the channelization code 1403 by amultiplier 1402, and constitutes one access slot of the CD_ICH frame1405. The CD_ICH frame 1405 is spread with a downlink scrambling code1407 by a multiplier 1406 and then transmitted.

The CA_ICH part 1411 is created by multiplying the signatures obtainedby repeating a signature of length 16 twice in a symbol unit by the signvalues of ‘1’, ‘−1’ or ‘0’ (indicating ACK, NAK, or Acquisition_Fail,respectively) on a symbol unit basis. The CA_ICH part 1411 cansimultaneously transmit ACK and NAK for several signatures. The CA_ICHpart 1411 is spread with the channelization code 1413 by a multiplier1412, and constitutes one access slot of the CA_ICH frame 1415. TheCA_ICH frame 1415 is spread with a downlink scrambling code 1417 by amultiplier 1416 before transmission.

FIG. 15 shows further another example of the second method, wherein theCD_ICH and the CA_ICH are spread with the same channelization code andsimultaneously transmitted using different signature groups.

Referring to FIG. 15, a CA_ICH part 1501 is created by multiplying thesignatures obtained by repeating a signature of length 16 twice in asymbol unit by the sign values of ‘1’, ‘−1’ or ‘0’ (indicating ACK, NAK,or Acquisition_Fail, respectively) on a symbol unit basis. The CA_ICHpart 1501 can simultaneously transmit ACK and NAK for severalsignatures. A k^(th) CA_ICH part 1503 is used when one CPCH channel isassociated with several CA signatures. A reason for associating one CPCHchannel with several CA signatures is to decrease the probability thatthe UE will use a CPCH which is not allocated by the UTRAN due to anerror occurred while the CA_ICH is transmitted from the UTRAN to the UE.Reference numeral 1505 of FIG. 15 indicates a CD_ICH part. The CD_ICHpart 1505 is identical to the CA_ICH part 1501 in physical structure.However, the CD_ICH part 1505 is orthogonal with the CA_ICH part 1501,since the CD_ICH part 1505 uses a signature selected from a signaturegroup different from the signature group used for the CA_ICH part.Therefore, even though the UTRAN simultaneously transmits the CD_ICH andthe CA_ICH, the UE cannot confuse the CD_ICH with the CA_ICH. The CA_ICHpart#1 1501 is added to the CA_ICH part#k 1503 by an adder 1502. TheCD_ICH part 1505 is added to the added CA_ICH part by an adder 1504, andthen spread with the orthogonal channelization code 1507 by a multiplier1506. The resulting spread value constitutes an indicator part of oneCD/CA_ICH slot, and the CD/CA_ICH is spread with a downlink scramblingcode 1510 by a multiplier 1508 before transmission.

In the method for simultaneously transmitting the CD_ICH and the CA_ICHby setting the transmission time different τ between the CD_ICH frameand the CA_ICH frame to ‘0’, the signatures for the AICH, shown in Table4, defined in the W-CDMA standard can be used. With regard to theCA_ICH, since the UTRAN designates one of several CPCH channels to theUE, =the UE receiver should attempt detecting several signatures. In theconventional AP_AICH and the CD_ICH, the UE would perform detection ononly one signature. However, when the CA_ICH according to thisembodiment of the present invention is used, the UE receiver shouldattempt detecting all the possible signatures. Therefore, there isrequired a method for designing or rearranging the structure ofsignatures for the AICH so as to decrease complexity of the UE receiver.

As described above, it will be assumed that the 16 signatures created bymultiplying 8 signatures out of 16 possible signatures by the signs(+1/−1) are allocated to the CD_ICH, and the 16 signatures created bymultiplying the remaining 8 signatures out of the 16 possible signaturesby the signs (+1/−1) are allocated to the CA_ICH for CPCH allocation.

In the W-CDMA standard, the signatures for the AICH use the Hadamardfunction, which is made in the following format.

Hn = Hn-1 Hn-1 Hn-1 −Hn-1 H1 = 1 1 1 −1

From this, the Hadamard function of length 16 required in the embodimentof the present invention is as follows. The signatures created by theHadamard function shown in Table 4 show the format given aftermultiplying the signatures by a channel gain A of the AICH, and thefollowing signatures show the format given before multiplying thesignatures by the channel gain A of the AICH.

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 => S0 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −11 −1 => S1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 => S2 1 −1 −1 1 1 −1−1 1 1 −1 −1 1 1 −1 −1 1 => S3 1 1 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1=> S4 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 => S5 1 1 −1 −1 −1 −1 1 11 1 −1 −1 −1 −1 1 1 => S6 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1 => S71 1 1 1 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 => S8 1 −1 1 −1 1 −1 1 −1 −1 1−1 1 −1 1 −1 1 => S9 1 1 −1 −1 1 1 −1 −1 −1 −1 1 1 −1 −1 1 1  => S10 1−1 −1 1 1 −1 −1 1 −1 1 1 −1 −1 1 1 −1  => S11 1 1 1 1 −1 −1 −1 −1 −1 −1−1 −1 1 1 1 1  => S12 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 1 −1 1 −1  => S13 11 −1 −1 −1 −1 1 1 −1 −1 1 1 1 1 −1 −1  => S14 1 −1 −1 1 −1 1 1 −1 −1 1 1−1 1 −1 −1 1  => S15

Eight of the above Hadamard functions are allocated to the CD_ICH andthe remaining eight Hadamard functions are allocated to the CA_ICH. Inorder to simply perform the fast Hadamard transform (FHT), thesignatures for the CA_ICH are allocated in the following sequence.

{S0, S8, S12, S2, S6, S10, S14}

Further, the signatures for the CD_ICH are allocated in the followingsequence.

{S1, S9, S5, S13, S3, S7, S11, S15}

Here, the signatures for the CA_ICH are allocated from left to right inorder to enable the UE to perform FHT, thereby minimizing thecomplexity. When 2, 4 and 8 signatures are selected from the signaturesfor the CA_ICH from left to right, the number of 1's is equal to thenumber of −1's in each column except the last column. By allocating thesignatures for the CD_ICH and the CA_ICH in the above manner, it ispossible to simplify the structure of the UE receiver for the number ofthe used signatures.

In addition, it is possible to associate the signatures to the CPCH orthe downlink channel for controlling the CPCH in another format. Forexample, the signatures for the CA_ICH can be allocated as follows.

[ 0, 8 ] => a maximum of 2 signatures are used [ 0, 4, 8, 12 ] => amaximum of 4 signatures are used [ 0, 2, 4, 6, 8, 10, 12, 14 ] => amaximum of 8 signatures are used

If NUM_CPCH (where 1<NUM_CPCH≦16) CPCHs are used, the signs (+1/−1)multiplied by the signatures associated with a k^(th) (k=0, . . . ,NUM_CPCH−1) CPCH (or a downlink channel for controlling the CPCH) aregiven as follows.CA _(—) sign _(—) sig[k]=(−1)[k mod 2]where CA_sign_sig[k] indicates the sign of +1/−1 multiplied by thek^(th) signature, and [k mod 2] indicates a remainder determined bydividing ‘k’ by 2. ‘x’ is defined as a number indicating a dimension ofthe signatures, which can be expressed as follows.x=2 if 0<NUM_CPCH≦44 if 4<NUM_CPCH≦88 if 8<NUM_CPCH≦16

Further, the used signatures are as follows.CA _(—) sig [k]=(16/x)*└k/2┘+1where └y┘ indicates that the maximum integer which does not exceed ‘y’.For example, when 4 signatures are used, they can be allocated asfollows.

S1 => 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 S5 => 1 1 1 1 −1 −1 −1 −1 1 1 1 1−1 −1 −1 −1 S9 => 1 1 1 1 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 S13 => 1 1 1 1−1 −1 −1 −1 −1 −1 −1 −1 1 1 1 1

As can be appreciated, if the signatures are allocated according to anembodiment of the present invention, the signatures have a format inwhich the Hadamard codes of length 4 are repeated four times. The UEreceiver adds the repeated 4 symbols and then takes FHT of length 4,when receiving the CA_ICH, thereby making it possible to highly decreasethe complexity of the UE.

Furthermore, in the CA_ICH signature mapping, the signature numbers forthe respective CPCH are added one by one. In this case, the consecutive2i^(th) and (2i+1)^(th) symbols have opposite signs, and the UE receiversubtracts the rear symbol from the front symbol out of the two despreadsymbols, so that it can be regarded as the same implementation.

On the contrary, the signatures for the CD_ICH can be allocated in thefollowing sequence. The easiest way of creating the signatures for thek^(th) CD_ICH is to increase the signature number one by one in theabove method for allocating the signatures for the CA_ICH. Anothermethod can be expressed as follow.CD _(—) sign _(—) sig[k]=(−1)[k mod 2]CD _(—) sig[k]=2*└k/2┘+2

That is, as described above, the CA_ICH is allocated in the sequence of[1, 3, 5, 7, 9, 11, 13, 15].

FIG. 16 shows a CA_ICH receiving device of the UE for the abovesignature structure. Referring to FIG. 16, a multiplier 1611 multipliesa signal received from an analog-to-digital (A/D) converter (not shown)by a spreading code W_(p) for the pilot channel to despread the receivedsignal, and provides the despread signal to a channel estimator 1613.The channel estimator 1613 estimates the size and phase of the downlinkchannel from the despread pilot channel signal. A complex conjugator1615 complex conjugates the output of the channel estimator 1613. Amultiplier 1617 multiplies the received signal by a Walsh spreading codeW_(AICH) for the AICH channel, and an accumulator 1619 accumulates theoutputs of the multiplier 1617 for a predetermined symbol period (e.g.256-chip period) and outputs despread symbols. A multiplier 1621multiplies the output of the accumulator 1619 by the output of thecomplex conjugator 1615 to modulate the input values, and provides theresulting output value to an FHT converter 1629. Receiving thedemodulated symbols, the FHT converter 1629 outputs signal strength foreach signature. A control and decision block 1631 receives the output ofthe FHT converter 1629 and decides a signature having the highestpossibility for the CA_ICH. In this embodiment of the present invention,the signature specified in the W-CDMA standard is used for the signaturestructure for the CA_ICH to simplify the structure of the UE receiver.Another allocation method will be described below, which is moreefficient than the method for using a part of the signatures for theCA_ICH.

In this new allocation method, 2^(K) signatures of length 2^(K) aregenerated. (If the 2^(K) signatures are multiplied by the signs of+1/−1, the number of the possible signatures can be 2^(K+1)). However,if only some of the signatures are used, rather than all, it isnecessary to more efficiently allocate the signatures in order todecrease complexity of the UE receiver. It will be assumed that Msignatures out of all possible signatures are used. Herein,2^(L−1)<M≦2^(L) and 1≦L≦K. The M signatures of length 2^(K) areconverted to the form in which each bit of the Hadamard function oflength 2^(L) is repeated 2^(K−L) times before transmission.

In addition, further another method for transmitting the ICH is to usesignatures other than the signatures used for the preamble. Thesesignatures are shown in Table 6 below.

A second embodiment of the present invention uses the signatures shownin Table 6 for the ICH signatures and allocates the CA_ICH so that theUE receiver may have low complexity. An orthogonal property ismaintained between the ICH signatures. Therefore, if the signaturesallocated to the ICH are efficiently arranged, the UE can easilydemodulate the CD_ICH by inverse fast Hadamard transform (IFHT).

TABLE 6 Preamble Symbol Signature P₀ P₁ P₂ P₃ P₄ P₅ P₆ P₇ P₈ P₉ P₁₀ P₁₁P₁₂ P₁₃ P₁₄ P₁₅ 1 A A A −A −A −A A −A −A A A −A A −A A A 2 −A A −A −A AA A −A A A A −A −A A −A A 3 A −A A A A −A A A −A A A A −A A −A A 4 −A A−A A −A −A −A −A −A A −A A −A A A A 5 A −A −A −A −A A A −A −A −A −A A −A−A −A A 6 −A −A A −A A −A A −A A −A −A A A A A A 7 −A A A A −A −A A A A−A −A −A −A −A −A A 8 A A −A −A −A −A −A A A −A A A A A −A A 9 A −A A −A−A A −A A A A −A −A −A A A A 10 −A A A −A A A −A A −A −A A A −A −A A A11 A A A A A A −A −A A A −A A A −A −A A 12 A A −A A A A A A −A −A −A −AA A A A 13 A −A −A A A −A −A −A A −A A −A A −A A A 14 −A −A −A A −A A AA A A A A A −A A A 15 −A −A −A −A A −A −A A −A A −A −A A −A −A A 16 −A−A A A −A A −A −A −A −A A −A A A −A A

In Table 6, let's say that n^(th) signature is represented by Sn and avalue determined by multiplying n^(th) signature by a sign ‘−1’ isrepresented by −Sn. The ICH signatures according to a second embodimentof the present invention are allocated as follows.

{S1, −S1, S2, −S2, S3, −S3, S14, −S14, S4, −S4, S9, −S9, S11, −S11, S15,−S15}

If the number of the CPCHs is smaller than 16, the signatures areallocated to the CPCHs from left to right so as to enable the UE toperform IFHT, thereby reducing the complexity. If 2, 4 and 8 signaturesare selected from {1, 2, 3, 14, 15, 9, 4, 11} from left to right, thenumber of A's is equal to the number of −A's in each column exceptingthe last column. Then, by rearranging (or permuting) the sequence of thesymbols and multiplying the rearranged symbols by a given mask, thesignatures are converted to an orthogonal code capable of performingIFHT.

FIG. 17 shows a structure of the UE receiver according to a secondembodiment of the present invention. Referring to FIG. 17, the UEdespreads an input signal for a 256-chip period to generatechannel-compensated symbol X_(i). If it is assumed that X_(i) indicatesan i^(th) symbol input to the UE receiver, a position shifter (orpermuter) 1723 rearranges X_(i) as follows.

-   -   Y={X₁₅, X₉, X₁₀, X₆, X₁₁, X₃, X₇, X_(1 X) ₁₃, X₁₂, X₁₄, X₄, X₈,        X₅, X₂, X₀}

A multiplier 1727 multiplies the rearranged value Y by the followingmask M generated by a mask generator 1725.

M={−1, −1, −1, −1, 1, 1, 1, −1, 1, −1, −1, 1, 1, 1, −1, −1}

Then, the signatures of S1, S2, S3, S14, S15, S9, S4 and S11 areconverted into S′1, S′2, S′3, S′14, S′15, S′9, S′4 and S′11, as follows.

S′1 = 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 S′2 = 1 1 1 1 1 1 1 1 −1 −1 −1 −1−1 −1 −1 −1 S′3 = 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 1 1 1 1 S′14 = 1 1 1 1−1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 S′15 = 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1−1 −1 S′9 = 1 1 −1 −1 1 1 −1 −1 −1 −1 1 1 −1 −1 1 1 S′4 = 1 1 −1 −1 −1−1 1 1 −1 −1 1 1 1 1 −1 −1 S′11 = 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 11

It can be understood that by rearranging the sequence of the inputsymbols and multiplying the rearranged symbols by a given mask, thesignatures are converted to an orthogonal code capable of performingIFHT. Further, it is not necessary to perform IFHT on the length 16, andit is possible to further decrease the complexity of the receiver byadding the repeated symbols and performing IFHT on the added symbols.That is, when 5 to 8 signatures are used (i.e., 9 to 16 CPCHs are used),two symbols are repeated. Thus, if the repeated symbols are added, IFHTis performed on only the length 8. In addition, when 3 to 4 signaturesare used (i.e., 5 to 8 CPCHs are used), 4 symbols are repeated, so thatIFHT can be performed after adding the repeated symbols. By efficientlyrearranging the signatures in this manner, it is possible to drasticallydecrease the complexity of the receiver.

The UE receiver of FIG. 17 is so constructed as to rearrange thedespread symbols and then multiply the rearranged symbols by a specificmask M. However, it is possible to obtain the same result even if thedespread symbols are first multiplied by a specific mask M beforerearrangement. In this case, it should be noted that the mask M has adifferent type.

In operation, a multiplier 1711 receives an output signal of an A/Dconverter (not shown) and multiplies the received signal by a spreadingcode W_(p) for the pilot channel to despread the received signal. Achannel estimator 1713 estimates the size and phase of the downlinkchannel from the despread pilot signal. A multiplier 1717 multiplies thereceived signal by a Walsh spreading code W_(AICH) for the AICH channel,and an accumulator 1719 accumulates the outputs of the multiplier 1717for a predetermined symbol period (e.g., 256-chip period) and outputsdespread symbols. For demodulation, the despread AICH symbols aremultiplied by the output of a complex conjugator 1715, which complexconjugates the output of the channel estimator 1713. The demodulatedsymbols are provided to a position shifter 1723, which rearranges theinput symbols such that the repeated symbols should neighbor to eachother. The output of the position shifter 1723 is multiplied by a maskoutput from a mask generator 1725 by a multiplier 1727 and provided toan FHT converter 1729. Receiving the output of the multiplier 1727, theFHT converter 1729 outputs signal strength of each signature. A controland decision block 1731 receives the output of the FHT converter 1729and decides the signature having the highest possibility for CA_ICH. InFIG. 17, it is possible to obtain the same results, although thelocations of the position shifter 1723, the mask generator 1725 and themultiplier 1727 are interchanged. Further, even if the UE receiver doesnot rearrange the position of the input symbols using the positionshifter 1723, it is also possible to previously appoint the positions atwhich the symbols are to be transmitted and use the positionalinformation when performing FHT.

Summarizing the embodiment of the CA_ICH signature structure accordingto the present invention, 2^(K) signatures of length 2^(K) aregenerated. (If the 2^(K) signatures are multiplied by the signs of+1/−1, the number of the possible signatures can be 2^(K+1)). However,if only some of the signatures are used, rather than all, it isnecessary to more efficiently allocate the signatures in order todecrease the complexity of the UE receiver. It will be assumed that Msignatures out of the whole signatures are used. Herein, 2^(L−1)<M≦2^(L)and 1≦L≦K. The M signatures of length 2^(K) are converted to the form inwhich each bit of the Hadamard function of length 2 is repeated 2^(K−L)times before transmission, when a specific mask is applied to (or XORedwith) the respective bits after permuting the symbols. Therefore, thisembodiment aims to simply perform FHT by multiplying the receivedsymbols by a specific mask and permuting the symbols at the UE receiver.

It is important not only to select the proper signatures used forallocating the CPCH channel, but also to allocate the data channel andcontrol channel for the uplink CPCH and a downlink control channel forcontrolling the uplink CPCH.

It is very important to allocate a data channel and a control channel ofthe uplink CPCH and allocate a downlink control channel for controllingthe uplink CPCH as well as to select the proper signatures used forassigning the CPCH channel.

First, the easiest method for allocating the uplink common channel is toallocate a downlink control channel over which the UTRAN transmits powercontrol information and an uplink common control channel over which theUE transmits a message, on a one-to-one basis. When the downlink controlchannel and the uplink common control channel are allocated on aone-to-one basis, it is possible to allocate the downlink controlchannel and the uplink common control channel by transmitting a commandonly once without a separate message. That is, this channel allocationmethod is applied when the CA_ICH designates the channels used for boththe downlink and the uplink.

A second method maps the uplink channel to the function of thesignatures for the AP, the slot number of the access channel and thesignatures for the CD_P, transmitted from the UE. For example, theuplink common channel is associated with an uplink channel correspondingto a slot number at a time point when the signature for the CD_P and itspreamble are transmitted. That is, in this channel allocation method,the CD_ICH allocates the channel used for the uplink, and the CA_ICHallocates the channel used for the downlink. If the UTRAN allocates thedownlink channel in this method, it is possible to maximally utilize theresources of the UTRAN, thereby increasing utilization efficiency of thechannels.

As another example of the method for allocating the uplink CPCH, sincethe UTRAN and the UE simultaneously know the signature for the APtransmitted from the UE and the CA_ICH received at the UE, the uplinkCPCH channel is allocated using the above two variables. It is possibleto increase capability of freely selecting the channels by associatingthe signatures for the AP with the data rate and allocating the CA_ICHto the uplink CPCH channel belonging to the data rate. Here, if thetotal number of the signatures for the AP is M and the number of theCA_ICHs is N, the number of selectable cases is M×N.

It will be assumed herein that the number of the signatures for the APis M=3 and the number of the CA_ICHs is N=4, as shown in Table 7 below.

TABLE 7 CA No received over CA_ICH Channel No CA(1) CA(2) CA(3) CA(4) APNo AP(1) 1 2 3 4 AP(2) 5 6 7 8 AP(3) 9 10 11 12

In Table 7, the signatures for the AP are AP(1), AP(2) and AP(3), andthe channel numbers allocated by the CA_ICH are CA(1), CA(2), CA(3) andCA(4). For channel allocation, if the channels are selected by theCA_ICH only, the number of allocable channels is 4. That is, when theUTRAN transmits CA(3) to the UE and the UE receives the transmittedCA(3), the UE allocates the 3^(rd) channel. However, since the UE andthe UTRAN know the AP number and the CA number, it is possible to themin combination. For example, in the case where the channels areallocated using the AP number and the CA number shown in Table 7, if theUE has transmitted AP(2) and the UTRAN has received CA(3), the UEselects the channel number 7 (2,3) rather than selecting the channelnumber 3. That is, from Table 7, it is possible to know the channelcorresponding to AP=2 and CA=3, and the information of Table 7 is storedin both the UE and the UTRAN. Therefore, the UE and the UTRAN may knowthat the allocated CPCH channel number is 7, by selecting the second rowand the third column of Table 7. As a result, the CHCP channel numbercorresponding to (2,3) is 7.

Therefore, the method for selecting the channel using the two variablesincreases the number of selectable channels. The UE and the UTRAN havethe information of Table 7 by signal exchange with their upper layers,or can calculate the information based on a formula. That is, it ispossible to determine an intersection and its associated number usingthe AP number in row and the CA number in column. At present, sincethere are 16 kinds of APs and there are 16 numbers which can beallocated by the CA_ACH, the number of the possible channels is16×16=256.

The information determined using the 16 kinds of the AP signatures andthe CA_ICH message means the scrambling code used when the PC_P and themessage of the uplink CPCH, the channelization code used for the uplinkCPCH, (i.e., the channelization code to be used for the uplink DPDCH andthe uplink DPCCH included in the uplink CPCH), and the channelizationcode for the downlink dedicated channel DL_DCH (i.e., the channelizationcode for the DL_DPCCH) for controlling power of the uplink CPCH.Regarding a method in which the UTRAN allocates a channel to the UE,since the AP signature requested by the UE is the maximum data ratedesired by the UE, the UTRAN selects an unused one of the correspondingchannels when it can allocate the maximum data rate requested by the UE.Subsequently, the UTRAN selects the signatures according to thefollowing rule for designating the signatures corresponding to thechannel and transmits the selected signatures.

Shown in FIGS. 30A and 30B is an embodiment in which, as describedabove, the UTRAN allocates to the UE the uplink scramble code, thechannelization code used for the scrambling code and the downlinkdedicated channel for power control of the uplink CPCH, using the 16kinds of the AP signatures and the CA_ICH message.

This method has the following disadvantages, when the UTRAN allocatesthe number of modems to a fixed value according to a data rate of thePCPCH. For example, assume that the UTRAN allocated 5 modems for a datarate 60 Kbps, 10 modems for a data rate 30 Kbps and 20 modems for a datarate 15 Kbps. In this circumstance, while the UEs belonging to the UTRANuse 20 15 Kbps PCPCHs, 7 30 Kbps PCPCHs and 3 60 Kbps PCPCHs, if anotherUE in the UTRAN requests the 15 Kbps PCPCH, the UTRAN cannot allocatethe requested 15 Kbps PCPCH to the UE due to lack of an extra 15 KbpsPCPCH.

Therefore, an embodiment of the present invention includes a method ofallocating the PCPCH to the UE even in the above situation, andproviding two or more data rates to a certain PCPCH so as to allocatethe PCPCH having a higher data rate as a PCPCH having a lower data rate,when necessary.

Before describing a first method in which the UTRAN transmitsinformation needed to use the CPCH to the UE using the AP signature andthe CA_ICH message, the following is assumed.

First, P_(SF) indicates the number of the PCPCHs with a specificspreading factor (SF), and a code number of a channelization code with aspecific spreading factor can be represented using the P_(SF). Forexample, the channelization code can be represented by Nod_(SF)(0),Nod_(SF)(1), Nod_(SF)(2), . . . , Nod_(SF)(P_(SF)−1). Among the Nod_(SF)values, the even Nod_(SF) values are used to spread the data part of theCPCH, and the odd Nod_(SF) values are used to spread the control part ofthe CPCH. The P_(SF) is equal to the number of modems used to demodulatethe uplink CPCH at the UTRAN, and may also be equal to the number of thedownlink dedicated channels allocated by the UTRAN in association withthe uplink CPCH.

Second, T_(SF) indicates the number of CA signatures used for a specificspreading factor, and a certain CA signature number used for a specificspreading factor can be represented using the T_(SF). For example, theCA signature number can be represented by CA_(SF)(0), CA_(SF)(1), . . ., CA_(SF)(T_(SF)−1).

Third, S_(SF) indicates the number of the AP signatures used for aspecific spreading factor, and a certain AP signature number used for aspecific spreading factor may be represented using the S_(SF). Forexample, the AP signature number may be represented by AP_(SF)(0),AP_(SF)(1), . . . , AP_(SF)(S_(SF)−1).

The above 3 parameters are determined by the UTRAN. A value obtained bymultiplying T_(SF) by S_(SF) must be equal to or larger than P_(SF), andthe S_(SF) may be set by the UTRAN considering a collision degreepermissible by the UEs using the CPCH in the process of transmitting theAP, and a utilization degree of the CPCH with the respective spreadingfactor (which is inversely proportional to the data rate). When theS_(SF) is set, T_(SF) is determined considering P_(SF).

Now, with reference to FIGS. 30A and 30B, a detailed description will bemade of the first method for transmitting the information necessary forthe CPCH to the UE using the AP signature and the CA message. In FIG.30A, reference numeral 3001 indicates a step where the UTRAN sets P_(SF)according to how may PCPCHs are to be used, and reference numeral 3002indicates a step of determining S_(SF) and T_(SF).

Reference numeral 3003 indicates a step of calculating M_(SF). TheM_(SF) is the minimum positive number C set such that a valueddetermined by multiplying a given positive number C by S_(SF) and thendividing the multiplied value by S_(SF) becomes 0. The M_(SF) is aperiod needed when the CA message indicates the same physical commonpacket channel (PCPCH). A reason for calculating M_(SF) is to allocatethe CA message such that the CA message should not repeatedly indicatethe same PCPCH at stated periods. In step 3003, the M_(SF) is calculatedbyM _(SF)=min {c: (C*S _(SF)) mod (P _(SF))≡0}

Reference numeral 3004 is a step of calculating a value n, whichindicates how many times the period of M_(SF) has been repeated. Forexample, n=0 means that the period of the CA message has never beenrepeated, and n=1 means that the period of the CA message has beenrepeated once. The value n is obtained in the process of searching for nsatisfying the following condition, wherein n starts from 0:n*M _(SF) *S _(SF) ≦i+j*S _(SF)<(n+1)*M _(SF) *S _(SF)where i denotes an AP signature number and j denotes a CA messagenumber.

Reference numeral 3005 is a step of calculating a sigma (σ) functionvalue. The σ function corresponds to permutation, and an abject ofcalculating the σ function is as follows. That is, if the CA messageperiodically indicates only a specific PCPCH, the CA message will have aperiodic property, so that it may not indicate other PCPCHs. Therefore,the a function is calculated to freely control the period of the CAmessage so as to prevent the CA message from having the period property,thus enabling the CA message to be able to freely indicate PCPCHs.

The σ is defined as:σ⁰(i)≡iσ¹(i)≡(i+1) mod S _(SF)σ^(n)(i)≡σ(σ^(n)(i))where i denotes an AP signature number, and an S_(SF) modulo operationis performed to prevent the σ value from exceeding the S_(SF) value andto enable the CA message to sequentially indicate the PCPCHs.

Reference numeral 3006 indicates a step of calculating a value k byreceiving an AP signature number i and a CA message number j, using theσ function value calculated in step 3005 and the value n calculated instep 3004. The value k indicates a channel number of the PCPCH with aspecific spreading factor or a specific data rate. The value kcorresponds on a one-to-one basis to the modem number allocated fordemodulation of the uplink PDPDH with the specific spreading factor orthe specific data rate. In addition, the value k can also correspond tothe scrambling code for the uplink PCPCH on a one-to-one basis.

As a result of calculating the value k, a channel number of the downlinkdedicated channel is determined which corresponds to the value k on aone-to-one basis. In other words, the channel number of the downlinkdedicated channel is determined in combination of the AP signaturenumber transmitted by the UE and the CA message allocated by the UTRAN,thus making it possible to control the uplink CPCH which corresponds tothe downlink dedicated channel.

In FIG. 30B, reference numeral 3007 indicates a step of determining arange m of the channelization code to determine which spreading factorcorresponds to the channelization code for the data part of the uplinkcommon channel corresponding on a one-to-one basis to the downlinkdedicated channel to which the value k calculated in step 3006 isdesignated. The range of the uplink channelization code is calculatedusing the following condition:P ₂ _(m−1) ≦k<P ₂ _(m)where P₂ _(m−1) denotes a channelization code (or OVSF code) with aspreading factor 2^(m−1), and P₂ _(m) denotes a channelization code (orOVSF code) with a spreading factor 2^(m). Hence, by using the value k,it is possible to know which spreading factor the channelization codeused in the message part of the uplink PCPCH has in the OVSF code tree.

Reference numeral 3008 is a step of determining a code number of thescrambling code to be used for the uplink PCPCH depending on the value kcalculated in step 3006 and the value m calculated in step 3007. Thecode number of the scrambling code corresponds to the uplink scramblingcode used for the PCPCH on a one-to-one basis, and the UE then spreadsPC_P and PCPCH using the scrambling code indicated by the scramblingcode number and transmits the spread values to the UTRAN.

The code number of the uplink scrambling code is calculated by

$\left\lfloor {{\sum\limits_{2 \leq u < {m - 1}}\;{\left( {P_{2^{n}} - P_{2^{a - 1}}} \right)/2^{a - 1}}} + {\left( {k - P_{2^{m - 1}}} \right)/2^{m}}} \right\rfloor$where k denotes the value calculated in step 3006 and m denotes thevalue calculated in step 3007.

Reference numeral 3009 indicates a step of determining a heading node ofthe channelization code used when the UE channelizes the message part ofthe uplink PCPCH. The heading node means a node, which coincides withthe value k, having the lowest spreading factor (or the highest datarate) in the branches of the OVSF code tree. After determining theheading node, the UE determines the channelization code to be useddepending on the spreading factor determined while receiving AP. Forexample, if k=4, the heading node coinciding with the value k has aspreading factor 16 and the UE desires a PCPCH with a spreading factor64, then the UE will select and use a channelization code with aspreading factor 64 from the heading node. There are two selectingmethods. In one method, a channelization code having a channelizationcode branch extending upward in the heading node, i.e., having aspreading factor 256, is used for a control part of the uplink PCPCH,and when it reaches a channelization code branch having the spreadingfactor requested by the UE out of the channelization code branchesextending downward in the heading node, a channelization code extendingupward from the above branch is used for the message part. In anothermethod, a channelization code with a spreading factor 256, created whilecontinuously extending downward from the lower branch of the headingnode is used for channel spreading the control part of the PCPCH, andwhen it reaches a channelization code branch having the spreading coderequested by the UE while continuously extending upward from the upperbranch of the heading node, the upper one of the two branches is usedfor channel spreading the message part.

Reference numeral 3010 indicates a step of determining a channelizationcode used to channel-spread the message part of the PCPCH using theheading node calculated in step 3009 and the spreading factor known tothe UE while transmitting the AP. In this step, the latter method wasused to determine the channelization code to be used by the UE. Thechannelization code is determined by a following formula:Channel Code Number=(Heading Node Number)*SF/2^(m−1)

It is possible to increase utilization of the PCPCH resources ascompared with the prior art, if the UTRAN allocates the information andchannel necessary for the PCPCH to the UE using the AP and the CAmessage in the method described with reference to FIGS. 30A and 30B.

Embodiments

A detailed description will be made of an algorithm for the first methodaccording to an embodiment of the present invention, in which the UTRANtransmits to the UE the information needed to use the CPCH using the APsignature and the CA_ICH message.

P_(4,2) = 1 AP₁ (=AP_(4,2)(0)), AP₂ (=AP_(4,2)(1)) P₄ = 1 AP₃ (=AP₄(0)),AP₄ (=AP₄(1)) P₈ = 2 AP₅ (=AP₈(0)), AP₆ (=AP₈(1)) P₁₆ = 4 AP₇(=AP₁₆(0)), AP₈ (=AP₁₆(1)) P₃₂ = 8 AP₉ (=AP₃₂(0)), AP₁₀ (=AP₃₂(1)) P₆₄ =16 AP₁₁ (=AP₆₄(0)), AP₁₂ (=AP₆₄(1)) P₁₂₈ = 32 AP₁₃ (=AP₁₂₈(0)), AP₁₄(=AP₁₂₈(1)) P₂₅₆ = 32 AP₁₅ (=AP₂₅₆(0)), AP₁₆ (=AP₂₅₆(1))

It will be assumed herein that all the 16 CAs can be used. Here, thenode values are searched using a given AP signature value and a CAsignature value provided from the UTRAN, as follows.

(1) For multi-code: P_(4,2)=1

F(AP₁,CA₀)=Nod_(4,2)(0)

F(AP₂,CA₀)=Nod_(4,2)(0)

(2) For SF=4: P₄=1

F(AP₃,CA₀)=Nod₄(0)

F(AP₄,CA₀)=Nod₄(0)

(3) For SF=8: P₈=2

F(AP₅,CA₀)=Nod₈(0), F(AP₆,CA₁)=Nod₈(0)

F(AP₆,CA₀)=Nod₈(1), F(AP₅,CA₁)=Nod₈(1)

(4) For SF=16: P₁₆=4

F(AP₇,CA₀)=Nod₁₆(0), F(AP₈,CA₂)=Nod₁₆(0)

F(AP₈,CA₀)=Nod₁₆(1), F(AP₇,CA₂)=Nod₁₆(1)

F(AP₇,CA₁)=Nod₁₆(2), F(AP₈,CA₃)=Nod₁₆(2)

F(AP₈,CA₁)=Nod₁₆(3), F(AP₇,CA₃)=Nod₁₆(3)

(5) For SF=32: P₃₂=8

F(AP₉,CA₀)=Nod₃₂(0), F(AP₁₀,CA₄)=Nod₃₂(0)

F(AP₁₀,CA₀)=Nod₃₂(1), F(AP₉,CA₄)=Nod₃₂(1)

F(AP₉,CA₁)=Nod₃₂(2), F(AP₁₀,CA₅)=Nod₃₂(2)

F(AP₁₀,CA₁)=Nod₃₂(3), F(AP₉,CA₅)=Nod₃₂(3)

F(AP₉,CA₂)=Nod₃₂(4), F(AP₁₀,CA₆)=Nod₃₂(4)

F(AP₁₀,CA₂)=Nod₃₂(5), F(AP₉,CA₆)=Nod₃₂(5)

F(AP₉,CA₃)=Nod₃₂(6), F(AP₁₀,CA₇)=Nod₃₂(6)

F(AP₁₀,CA₃)=Nod₃₂(7), F(AP₉,CA₇)=Nod₃₂(6)

(6) For SF=64: P₆₄=16

F(AP₁₁,CA₀)=Nod₆₄(0), F(AP₁₂,CA₈)=Nod₆₄(0)

F(AP₁₂,CA₀)=Nod₆₄(1), F(AP₁₁,CA₈)=Nod₆₄(1)

F(AP₁₁,CA₁)=Nod₆₄(2), F(AP₁₂,CA₉)=Nod₆₄(2)

F(AP₁₂,CA₁)=Nod₆₄(3), F(AP₁₁,CA₉)=Nod₆₄(3)

F(AP₁₁,CA₂)=Nod₆₄(4), F(AP₁₂,CA₁₀)=Nod₆₄(4)

F(AP₁₂,CA₂)=Nod₆₄(5), F(AP₁₁,CA₁₀)=Nod₆₄(5)

F(AP₁₁,CA₃)=Nod₆₄(6), F(AP₁₂,CA₁₁)=Nod₆₄(6)

F(AP₁₂,CA₃)=Nod₆₄(7), F(AP₁₁,CA₁₁)=Nod₆₄(7)

F(AP₁₁,CA₄)=Nod₆₄(8), F(AP₁₂,CA₁₂)=Nod₆₄(8)

F(AP₁₂,CA₄)=Nod₆₄(9), F(AP₁₁,CA₁₂)=Nod₆₄(9)

F(AP₁₁,CA₅)=Nod₆₄(10), F(AP₁₂,CA₁₃)=Nod₆₄(10)

F(AP₁₂,CA₅)=Nod₆₄(11), F(AP₁₁,CA₁₃)=Nod₆₄(11)

F(AP₁₁,CA₆)=Nod₆₄(12), F(AP₁₂,CA₁₄)=Nod₆₄(12)

F(AP₁₂,CA₆)=Nod₆₄(13), F(AP₁₁,CA₁₄)=Nod₆₄(13)

F(AP₁₁,CA₇)=Nod₆₄(14), F(AP₁₂,CA₁₅)=Nod₆₄(14)

F(AP₁₂,CA₇)=Nod₆₄(15), F(AP₁₁,CA₁₅)=Nod₆₄(15)

(7) For SF128: P₁₂₈=32

F(AP₁₃,CA₀)=Nod₁₂₈(0)

F(AP₁₄,CA₀)=Nod₁₂₈(1)

F(AP₁₃,CA₁)=Nod₁₂₈(2)

F(AP₁₄,CA₁)=Nod₁₂₈(3)

F(AP₁₃,CA₂)=Nod₁₂₈(4)

F(AP₁₄,CA₂)=Nod₁₂₈(5)

F(AP₁₃,CA₃)=Nod₁₂₈(6)

F(AP₁₄,CA₃)=Nod₁₂₈(7)

F(AP₁₃,CA₄)=Nod₁₂₈(8)

F(AP₁₄,CA₄)=Nod₁₂₈(9)

F(AP₁₃,CA₅)=Nod₁₂₈(10)

F(AP₁₄,CA₅)=Nod₁₂₈(11)

F(AP₁₃,CA₆)=Nod₁₂₈(12)

F(AP₁₄,CA₆)=Nod₁₂₈(13)

F(AP₁₃,CA₇)=Nod₁₂₈(14)

F(AP₁₄,CA₇)=Nod₁₂₈(15)

F(AP₁₃,CA₈)=Nod₁₂₈(16)

F(AP₁₄,CA₈)=Nod₁₂₈(17)

F(AP₁₃,CA₉)=Nod₁₂₈(18)

F(AP₁₄,CA₉)=Nod₁₂₈(19)

F(AP₁₃,CA₁₀)=Nod₁₂₈(20)

F(AP₁₄,CA₁₀)=Nod₁₂₈(21)

F(AP₁₃,CA₁₁)=Nod₁₂₈(22)

F(AP₁₄,CA₁₁)=Nod₁₂₈(23)

F(AP₁₃,CA₁₂)=Nod₁₂₈(24)

F(AP₁₄,CA₁₂)=Nod₁₂₈(25)

F(AP₁₃,CA₁₃)=Nod₁₂₈(26)

F(AP₁₄,CA₁₃)=Nod₁₂₈(27)

F(AP₁₃,CA₁₄)=Nod₁₂₈(28)

F(AP₁₄,CA₁₄)=Nod₁₂₈(29)

F(AP₁₃,CA₁₅)=Nod₁₂₈(30)

F(AP₁₄,CA₁₅)=Nod₁₂₈(31)

(8) For SF=256: P₂₅₆=32

F(AP₁₅,CA₀)=Nod₂₅₆(0)

F(AP₁₆,CA₀)=Nod₂₅₆(1)

F(AP₁₅,CA₁)=Nod₂₅₆(2)

F(AP₁₆,CA₁)=Nod₂₅₆(3)

F(AP₁₅,CA₂)=Nod₂₅₆(4)

F(AP₁₆,CA₂)=Nod₂₅₆(5)

F(AP₁₅,CA₃)=Nod₂₅₆(6)

F(AP₁₆,CA₃)=Nod₂₅₆(7)

F(AP₁₅,CA₄)=Nod₂₅₆(8)

F(AP₁₆,CA₄)=Nod₂₅₆(9)

F(AP ₁₅,CA₅)=Nod₂₅₆(10)

F(AP ₁₆,CA₅)=Nod₂₅₆(11)

F(AP ₁₅,CA₆)=Nod₂₅₆(12)

F(AP₁₆,CA₆)=Nod₂₅₆(13)

F(AP₁₅,CA₇)=Nod₂₅₆(14)

F(AP₁₆,CA₇)=Nod₂₅₆(15)

F(AP₁₅,CA₈)=Nod₂₅₆(16)

F(AP₁₆,CA₈)=Nod₂₅₆(17)

F(AP₁₅,CA₉)=Nod₂₅₆(18)

F(AP₁₆,CA₉)=Nod₂₅₆(19)

F(AP₁₅,CA₁₀)=Nod₂₅₆(20)

F(AP₁₆,CA₁₀)=Nod₂₅₆(21)

F(AP₁₅,CA₁₁)=Nod₂₅₆(22)

F(AP₁₆,CA₁₁)=Nod₂₅₆(23)

F(AP₁₅,CA₁₂)=Nod₂₅₆(24)

F(AP₁₆,CA₁₂)=Nod₂₅₆(25)

F(AP₁₅,CA₁₃)=Nod₂₅₆(26)

F(AP₁₆,CA₁₃)=Nod₂₅₆(27)

F(AP₁₅,CA₁₄)=Nod₂₅₆(28)

F(AP₁₆,CA₁₄)=Nod₂₅₆(29)

F(AP₁₅,CA₁₅)=Nod₂₅₆(30)

F(AP₁₆,CA₁₅)=Nod₂₅₆(31)

The foregoing can be expressed using Table 8 below, which shows achannel mapping relationship according to the embodiment of the presentinvention. The necessary scrambling code number and channelization codenumber can be determined as shown in Table 8. When the UE uses itsunique scrambling code, the scrambling code number is coincident withthe PCPCH number and the channelization codes are all 0.

TABLE 8 PCP Scrambling CH Code Channelization Num Num Code Num SF = 4 SF= 8 SF = 16 SF = 32 SF = 64 SF = 128 SF = 256 0 1 SF4–0 Nod₄(0) Nod₈(0)Nod₁₆(0) Nod₃₂(0) Nod₆₄(0) Nod₁₂₈(0) Nod₂₅₆(0) 1 1 SF8-4 Nod₈(1)Nod₁₆(1) Nod₃₂(1) Nod₆₄(1) Nod₁₂₈(1) Nod₂₅₆(1) 2 1 SF16-12 Nod₁₆(2)Nod₃₂(2) Nod₆₄(2) Nod₁₂₈(2) Nod₂₅₆(2) 3 1 SF16-14 Nod₁₆(3) Nod₃₂(3)Nod₆₄(3) Nod₁₂₈(3) Nod₂₅₆(3) 4 2 SF32-0  Nod₃₂(4) Nod₆₄(4) Nod₁₂₈(4)Nod₂₅₆(4) 5 2 SF32-2  Nod₃₂(5) Nod₆₄(5) Nod₁₂₈(5) Nod₂₅₆(5) 6 2 SF32-4 Nod₃₂(6) Nod₆₄(6) Nod₁₂₈(6) Nod₂₅₆(6) 7 2 SF32-6  Nod₃₂(7) Nod₆₄(7)Nod₁₂₈(7) Nod₂₅₆(7) 8 2 SF64-16 Nod₆₄(8) Nod₁₂₈(8) Nod₂₅₆(8) 9 2 SF64-18Nod₆₄(9) Nod₁₂₈(9) Nod₂₅₆(9) 10 2 SF64-20 Nod₆₄(10) Nod₁₂₈(10)Nod₂₅₆(10) 11 2 SF64-22 Nod₆₄(11) Nod₁₂₈(11) Nod₂₅₆(11) 12 2 SF64-24Nod₆₄(12) Nod₁₂₈(12) Nod₂₅₆(12) 13 2 SF64-26 Nod₆₄(13) Nod₁₂₈(13)Nod₂₅₆(13) 14 2 SF64-28 Nod₆₄(14) Nod₁₂₈(14) Nod₂₅₆(14) 15 2 SF64-30Nod₆₄(15) Nod₁₂₈(15) Nod₂₅₆(15) 16 2 SF128-64  Nod₁₂₈(16) Nod₂₅₆(16) 172 SF128-66  Nod₁₂₈(17) Nod₂₅₆(17) 18 2 SF128-68  Nod₁₂₈(18) Nod₂₅₆(18)19 2 SF128-70  Nod₁₂₈(19) Nod₂₅₆(19) 20 2 SF128-72  Nod₁₂₈(20)Nod₂₅₆(20) 21 2 SF128-74  Nod₁₂₈(21) Nod₂₅₆(21) 22 2 SF128-76 Nod₁₂₈(22) Nod₂₅₆(22) 23 2 SF128-78  Nod₁₂₈(23) Nod₂₅₆(23) 24 2SF128-80  Nod₁₂₈(24) Nod₂₅₆(24) 25 2 SF128-82  Nod₁₂₈(25) Nod₂₅₆(25) 262 SF128-84  Nod₁₂₈(26) Nod₂₃₆(26) 27 2 SF128-86  Nod₁₂₈(27) Nod₂₅₆(27)28 2 SF128-88  Nod₁₂₈(28) Nod₂₅₆(28) 29 2 SF128-90  Nod₁₂₈(29)Nod₂₅₆(29) 30 2 SF128-92  Nod₁₂₈(30) Nod₂₅₆(30) 31 2 SF128-94 Nod₁₂₈(31) Nod₂₅₆(31)

Table 8 shows an example in which several UEs can simultaneously use onescrambling code. However, when each UE uses a unique scrambling code,the scrambling code number in Table 8 is identical to the PCPCH numberand the channelization code numbers are all 0 or 1 in an SF=4 node.

Reference numerals 3001 to 3006 of FIG. 30A are the steps of calculatingthe PCPCH number k with a specific spreading factor or a specific datarate. Unlike the method used in steps 3001 to 3006 of FIG. 30A, there isanother method for determining the value k using the AP signature numberi and the CA signature number j.

The second method determines the value k using the AP and the CA messagein accordance with the following formula:F(AP _(SF)(i),CA _(SF)(j))=Nod _(SF)(i*M _(SF) +j mod P _(SF)) for j<M_(SF)M_(SF)=min(P_(SF),T_(SF))

where AP_(SF)(i) denotes an i^(th) signature out of the AP signatureswith a specific spreading factor and CA_(SF)(j) denotes a j^(th) messageout of the CA signatures with a specific spreading factor. The Ffunction indicates the uplink PCPCH number k that the UTRAN allocates tothe UE using the AP signature number and the CA signature number at thespecific spreading factor. M_(SF) in the foregoing formula is differentin meaning from M_(SF) of FIG. 30A. M_(SF) of FIG. 30A is a periodneeded when the CA message indicates the same PCPCH, whereas M_(SF) inthe foregoing formula indicates a smaller value out of the total numberof the PCPCHs with a specific spreading factor and the total number ofCA messages used at a specific spreading factor. The foregoing formulacannot be used, when the CA signature number is less than M_(SF) at thespecific spreading factor. That is, if the total number of the CAsignatures used at the specific spreading factor is smaller than thenumber of the PCPCHs, the CA signature number transmitted to the UE bythe UTRAN should be set to a value smaller than the total number of theCA signatures. If, however, the total number of the PCPCHs used at thespecific spreading factor is smaller than the number of the CAsignatures, the CA signature number transmitted to the UE by the UTRANshould be set to a value smaller than the total number of the PCPCHs.The reason for defining the range as stated above is to allocate thePCPCHs by the number of the CA signatures, with the AP signature numberfixed in the formula of the foregoing second method. When the UTRANallocates the PCPCHs to the UE using the multiple CA signatures, thereis a case where the number of the PCPCHs with the specific spreadingfactor is larger than the number of the CA messages. In this case, thenumber of the CA signatures is insufficient, so that the UTRAN allocatesthe PCPCHs using the AP signatures transmitted from the UE. In theforegoing formula, the value k of the uplink PCPCH number is determinedby performing a modulo P_(SF) operation on the CA signature number j anda value obtained by multiplying M_(SF) by the AP signature number i.When the number of the CA signatures is smaller than the number of thePCPCHs after the modulo operation, the UTRAN can allocate the PCPCHsusing even the AP, and when the number of the CA signatures is largerthan the number of the PCPCHs, the UTRAN can use the CA signatures asmany as it requires, through the modulo operation.

The major difference between the foregoing first and second methods forallocating the uplink PCPCH using the AP signature number i and the CAsignature number j is as follows. The first method allocates the PCPCHusing the AP signature number with the CA signature number fixed, whilethe second method allocates the PCPCH using the CA signature number withthe AP signature number fixed.

The value k calculated by the formula used in the second method is usedin step 3007 of FIG. 30B to calculate the spreading factor of thechannelization code used for the data part of the uplink PCPCH. Thecalculation result of step 3007 and the value k determine the uplinkscrambling code number to be used for the uplink PCPCH. The heading nodenumber is determined in step 3009, and the channelization code numberused for the unlink PCPCH is determined in step 3010. The steps 3007 to3010 are equal to the first method for allocating the uplink PCPCH usingthe AP signature number and the CA signature number.

A third method for allocating the uplink PCPCH using the AP signaturenumber i and the CA signature number j, uses the following formulas.P_(SF)≦T_(SF)→F(AP_(SF)(i),CA_(SF)(j))=Nod_(SF)(j)P _(SF) >T _(SF) →F(AP _(SF)(i),CA _(SF)(j))=Nod_(SF)(σ^((n))(i)+((j−1)*S _(SF) mod P _(SF)))

The third method compares the total number of the PCPCHs with a specificdata rate or a specific spreading factor with the total number of the CAsignatures and uses different formulas for determining the uplink PCPCHnumber k. A first one of the foregoing formulas of the third method isused when the number of the PCPCHs is smaller than or equal to thenumber of the CA signatures, and in this formula, the CA signaturenumber j becomes the uplink PCPCH number k.

A second one of the foregoing formulas of the third method is used whenthe number of the uplink PCPCHs is larger than the number of the CAsignatures. In this formula, the σ function is identical to the σfunction calculated in step 3005 of FIG. 30A, and this σ functionenables the CA message to sequentially indicate the PCPCHs. In thisformula, performing a modulo P_(SF) operation on the value determined bymultiplying the total number of the AP signatures by the CA signaturenumber subtracted by 1 is to prevent the uplink PCPCH number k frombeing higher than the total number of the uplink PCPCHs, set at aspecific spreading factor.

The value k calculated in the foregoing formula is used in steps 3007 to3010 where the UTRAN allocates the uplink PCPCH to the UE.

Such an operation will be described with reference to FIGS. 18 and 19. Acontroller 1820 of the UE and a controller 1920 of the UTRAN canallocate the common packet channels having the structure of Table 7, byusing either the CPCH allocating information of Table 7 includedtherein, or the calculating method stated above. It will be assumed inFIGS. 18 and 19 that the controllers 1820 and 1920 include theinformation of Table 7.

The controller 1820 of the UE determines, when communication over theCPCH is required, an AP signature corresponding to a desired data rate,and transmits the determined AP signature through a preamble generator1831 which multiplies the determined AP signature by the scrambling codein a unit of a chip. Upon receipt of the AP preamble, the UTRAN examinesthe signature used for the AP preamble. If the received signature is notused by another UE, the UTRAN creates the AP_AICH using the receivedsignature. Otherwise, if the received signature is used by another UE,the UTRAN creates the AP_AICH using a signature value obtained byinverting the phase of the received signature. Upon receipt of an APpreamble for which a different signature is used by another UE, theUTRAN examines whether to use the received signature and creates theAP_AICH using the inversed or in-phase signature of the receivedsignature. Thereafter, the UTRAN creates the AP_AICH by adding thegenerated AP_AICH signals and thus, can transmit the status of thesignatures. Upon receipt of an AP_AICH using the same signature as thetransmitted signature, the UE creates the CD_P using any one of thesignatures for detecting collision and transmits the created CD_P. Uponreceipt of the signature included in the CD_P from the UE, the UTRANtransmits the CD_ICH using the same signature as the signature used forthe CD_P. At the same time, if the UTRAN receives the CD_P through apreamble detector 1911, the controller 1920 of the UTRAN detects CPCHallocation request, creates a CA_ICH and transmits the CA_ICH to the UE.As stated above, the CD_ICH and the CA_ICH can be transmitted eithersimultaneously or separately. Describing operation of generating theCA_ICH, the UTRAN determines an unused scrambling code out of thescrambling codes corresponding to the data rate requested by the UEaccording to the signatures requested in the AP by the UE, i.e., thedesignated CA_ICH signature of Table 7. The determined CA_ICH signatureis combined with the signature used for the AP preamble, creatinginformation for allocating the CPCH. The controller 1920 of the UTRANallocates the CPCH by combining the determined CA_ICH signature with thereceived AP signature. Further, the UTRAN receives the determined.CA_ICH signature information through an AICH generator 1931 to generatethe CA_ICH. The CA_ICH is transmitted to the UE through a frameformatter 1933. Upon receipt of the CA_ICH signature information, the UEallocates the common packet channel in the above manner, using thesignature information of the transmitted AP and the received CA_ICHsignature.

FIG. 18 shows a structure of the UE for receiving AICH signals,transmitting preambles, and, in general, communicating a message over anuplink CPCH according to an embodiment of the present invention.

Referring to FIG. 18, an AICH demodulator 1811 demodulates AICH signalson the downlink transmitted from the AICH generator of the UTRAN,according to a control message 1822 for channel designation, providedfrom the controller 1820. The AICH demodulator 1811 may include anAP_AICH demodulator, a CD_ICH demodulator and a CA_ICH demodulator. Inthis case, the controller 1820 designates the channels of the respectivedemodulators to enable them to receive AP_AICH, CD_ICH and CA_ICH,respectively, transmitted from the UTRAN. The AP_AICH, CD_ICH and CA_ICHcan be implemented by either one demodulator or separate demodulators.In this case, the controller 1820 can designate the channels byallocating the slots to receive the time-divided AICHs.

A data and control signal processor 1813 designates a channel under thecontrol of the controller 1820, and processes data or a control signal(including a power control command) received over the designatedchannel. A channel estimator 1815 estimates strength of a signalreceived from the UTRAN over the downlink, and controls phasecompensation and gain of the data and control signal processor 1813 toassist demodulation.

The controller 1820 controls the overall operation of a downlink channelreceiver and an uplink channel transmitter of the UE. In this embodimentof the present invention, the controller 1820 controls generation of theaccess preamble AP and the collision detection preamble CD_P whileaccessing the UTRAN using a preamble generating control signal 1826,controls transmission power of the uplink using an uplink power controlsignal 1824, and processes the AICH signals transmitted from the UTRAN.That is, the controller 1820 controls the preamble generator 1831 togenerate the access preamble AP and the collision detection preambleCD_P as shown by 331 of FIG. 3, and controls the AICH demodulator 1811to process the AICH signals generated as shown by 301 of FIG. 3.

The preamble generator 1831, under the control of the controller 1820,generates the preambles AP and CD_P as shown by 331 of FIG. 3. A frameformatter 1833 formats frame data by receiving the preambles AP and CD_Poutput from the preamble generator 1831, and the packet data and pilotsignals on the uplink. The frame formatter 1833 controls transmissionpower of the uplink according to the power control signal output fromthe controller 1820, and can transmit another uplink transmission signal1832 such as a power control preamble and data after being allocated aCPCH from the UTRAN. In this case, it is also possible to transmit apower control command for controlling transmission power of the downlinkover the uplink.

FIG. 19 shows a transceiver of the UTRAN for receiving preambles,transmitting AICH signals, and, in general, communicating a message overan uplink CPCH according to an embodiment of the present invention.

Referring to FIG. 19, an AICH detector 1911 detects the AP and the CD_Pshown by 331 of FIG. 3, transmitted from the UE, and provides thedetected AP and CD_P to the controller 1920. A data and control signalprocessor 1913 designates a channel under the control of the controller1920, and processes data or a control signal received over thedesignated channel. A channel estimator 1915 estimates strength of asignal received from the UE over the downlink, and controls a gain ofthe data and control signal processor 1913.

The controller 1920 controls the overall operation of a downlink channeltransmitter and an uplink channel receiver of the UTRAN. Based on apreamble select control command 1922, the controller 1920 controlsdetection of the access preamble AP and the collision detection preambleCD_P generated when the UE accesses the UTRAN, and controls generationof the AICH signals for responding to the AP and CD_P and commandingchannel allocation. That is, the controller 1920 controls the AICHgenerator 1931 using an AICH generation control command 1926 to generatethe AICH signals shown by 301 of FIG. 3, upon detecting the accesspreamble AP and the collision detection preamble CD_P received throughthe preamble detector 1911.

The AICH generator 1931, under the control of the controller 1920,generates AP_AICH, CD_ICH and CA_ICH which are response signals to thepreamble signals. The AICH generator 1931 may include an AP_AICHgenerator, a CD_ICH generator and a CA_ICH generator. In this case, thecontroller 1920 designates the generators so as to generate the AP_AICH,CD_ICH and CA_ICH shown by 301 of FIG. 3, respectively. The AP_AICH,CD_ICH and CA_ICH can be implemented by either one generator or separategenerators. In this case, the controller 1920 can allocate thetime-divided slots of the AICH frame so as to transmit the AP_AICH,CD_ICH and CA_ICH.

A frame formatter 1933 formats frame data by receiving the AP_AICH,CD_ICH and CA_ICH output from the AICH generator 1931, and the downlinkcontrol signals, and controls transmission power of the uplink accordingto the power control command 1924 output from the controller 1920.Further, when a downlink power control command 1932 is received over theuplink, the frame formatter 1933 may control transmission power of andownlink channel for controlling the common packet channel according tothe power control command.

The embodiment of the present invention includes one method in which theUTRAN performs outer-loop power control using the downlink dedicatedchannel established in association with the uplink CPCH on a one-to-onebasis, and another method in which the UTRAN transmits a CA confirmationmessage to the UE.

The downlink physical dedicated channel is comprised of a downlinkphysical dedicated control channel and a downlink physical dedicateddata channel. The downlink physical dedicated control channel iscomprised of a 4-bit pilot, a 2-bit uplink power control command and a0-bit TFCI (Transport Format Combination Indicator), and the downlinkphysical dedicated data channel is comprised of 4-bit data. The downlinkphysical dedicated channel corresponding to the uplink CPCH is spreadwith a channelization code with a spreading factor 512 and transmittedto the UE.

In the method for performing outer-loop power control using the downlinkphysical dedicated channel, the UTRAN sends a bit pattern previouslyscheduled with the UE using the TFCI part or the pilot part of thedownlink physical dedicated data channel and the downlink physicaldedicated control channel, to enable the UE to measure a bit error rate(BER) of the downlink physical dedicated data channel and a BER of thedownlink physical dedicated control channel and transmit the measuredvalues to the UTRAN. The UTRAN then performs the outer-loop powercontrol using the measured values.

The “bit pattern” previously scheduled between the UTRAN and the UE maybe a channel allocation confirmation message, a specific bit patterncorresponding to the channel allocation confirmation message on aone-to-one basis, or a coded bit stream. The “channel allocationconfirmation message” refers to a confirmation message for the CPCHallocated by the UTRAN at the request of the UE.

The channel allocation confirmation message transmitted to the UE by theUTRAN, the specific bit pattern corresponding to the channel allocationconfirmation message on a one-to-one basis or the coded bit stream canbe transmitted using a data part of the downlink physical dedicated datachannel corresponding to the uplink CPCH and the TFCI part of thedownlink physical dedicated control channel.

The transmission method using the data part of the downlink physicaldedicated data channel is divided into one method for repeatedlytransmitting the 4-bit or 3-bit channel allocation confirmation messagefor the 4-bit data part without encoding, and another method fortransmitting the channel allocation confirmation after encoding. The3-bit channel allocation confirmation message is used when allocatingthe uplink CPCH to the UE using 2 signatures. In this case, the downlinkphysical dedicated channel structure is comprised of a 4-bit data part,a 4-bit pilot part and a 2-bit power control command part.

The transmission method using the TFCI part of the downlink physicaldedicated control channel allocates, to the TFCI part, 2 of the 4 bitsassigned to the data part of the downlink physical dedicated channel,and transmits coded symbols to the 2-bit TFCI part. The 2-bit TFCI partis transmitted at one slot, and 30 bits are transmitted for one framecomprised of 15 slots. For a method for encoding the bits transmitted tothe TFCI part, a (30,4) encoding method or a (30,3) encoding method istypically used, which can be implemented by using 0-fading in a (30,6)encoding method used to transmit the TFCI in the conventional W-CDMAstandard. In this case, the downlink physical dedicated channelstructure is comprised of a 2-bit data part, a 2-bit TFCI part, a 2-bitTPC and a 4-bit pilot.

In the foregoing two transmission methods, it is possible to measure thebit error rate for outer-loop power control using the downlink physicaldedicated channel. In addition, it is possible to confirm channelallocation of the CPCH by transmitting the channel allocationconfirmation message or the bit stream corresponding to the channelallocation confirmation message on a one-to-one basis, which is known toboth the UTRAN and the UE, thereby ensuring stable CPCH channelallocation.

When transmitting one frame of the downlink dedicated channel, N slotsof the frame can transmit a pattern previously scheduled between theUTRAN and the UE to measure the bit error rate, and the remaining (15−N)slots of the frame can be used to transmit the channel allocationconfirmation message. Alternatively, when transmitting the downlinkdedicated channel, a specific frame can be used to transmit the patternpreviously scheduled between the UTRAN and the UE to measure the biterror rate, and another specific frame can be used to transmit thechannel allocation confirmation message. As an example of the foregoingtransmission method, the first one or two frames of the downlinkphysical dedicated channel can be used to transmit the channelallocation message, and the succeeding frames can be used to transmitthe bit pattern previously scheduled between the UTRAN and the UE tomeasure the bit error rate of the downlink dedicated channel.

FIG. 33 shows a signal and data flow between the UTRAN and the UEaccording to an embodiment of the present invention, proposed for uplinkouter-loop power control of the outer-loop power control. Downlinkouter-loop power control of the outer-loop power control can beperformed in the same method as used for downlink outer-loop powercontrol of the dedicated channel in the W-CDMA standard.

Before describing FIG. 33, the terminologies shown in FIG. 33 will firstbe defined. The terminologies defined below are commonly used in theW-CDMA standard.

Reference numeral 3301 of FIG. 33 indicates a UE (user equipment). NodeB 3311, DRNC 3321 and SRNC 3331 are included in the UTRAN. The Node Bcorresponds to a base station in an asynchronous mobile communicationsystem, and the DRNC (Drift Radio Network Controller) and the SRNC(Serving Radio Network Controller) constitute an RNC (Radio NetworkController) which has the function of managing the Node B in the UTRAN.The RNC has the function similar to that of the base station controllerin the synchronous mobile communication system. The SRNC and the DRNCare distinguished from the standpoint of the UE. When the UE isconnected to a specific Node B and connected to a core network of theasynchronous mobile communication network through the RNC which managesthe Node B, the RNC serves as the SRNC. However, when the UE isconnected to a specific Node B and connected to a core network of theasynchronous mobile communication network through an RNC which does notmanage the Node B, the RNC serves as the DRNC.

In FIG. 33, Uu 3351 is an interface between the UE and the Node B, lub3353 is an interface between the Node B and the RNC, and lur 3357 is aninterface between the DRNC and the SRNC.

A signal and control flow between the UE and the UTRAN to performouter-loop power control on the CPCH is as follows. Reference numerals3302 and 3304 indicate user data #1 and user data #n transmitted over anuplink PCPCH 3303 and an uplink 3305 in a unit of TTI (Transmit TimeInterval), respectively. For convenience of explanation, the user #1 andthe user #n are assumed to be connected to the same Node B and RNC. TheTTI is a time unit in which an upper layer of the physical layertransmits data, and the W-CDMA standard uses 10, 20, 40 and 80 ms forthe TTI. The user data 3302 and the user data 3304 transmitted over thePCPCHs 3303 and 3305 are received at the Node B 3311. The Node B 3311performs CRC (Cyclic Redundancy Check) in a transmission block unit andindicates the CRC check results using CRCI (CRC indicator). The CRC andthe CRCI are transmitted together with QE (Quality Estimate=bit errorrate of the physical channel). Reference numerals 3312 and 3314 indicatemessages added to the lub CPCH data frames 3313 and 3315. The CRCI isadded to every transmission block, and the CPCH data frames 3313 and3315 transmitted over the lub are transmitted to the RNC 3321 at everyTTI.

For convenience of explanation, the RNC 3321 is assumed to be the DRNC.Upon receipt of the lub CPCH data frames 3313 and 3315 transmitted fromthe Node B 3311, the RNC 3321 analyzes an SRNTI value by analyzing theheader of the transmission block in the data frames. The SRNTI value isa temporary indicator given in the SRNC to identify the UE. When the UEaccesses the SRNC, the SRNC assigns one SRNTI to the corresponding UE.The DRNC or the Node B can inform the SRNC, by using the SRNTI, fromwhich UE the presently transmitted data has been received. Upondetecting the SRNTI value, the DRNC 3321 assembles the header-removedMAC-c SDU (Service Data Unit), CRCI and QE and transmits the assembleddata together with lur data frames 3323 and 3325 to the SRNC 3331. TheMAC-c is a MAC (Medium Access Control) message used for the commonchannel during medium access control. The SRNC 3331 obtains informationnecessary for outer-loop power control of the CPCH by analyzing the lurdata frames 3323 and 3325 transmitted from the DRNC 3321. The “necessaryinformation” may be QE of the uplink PCPCH or CRCI. It is possible tocalculate Eb/No 3332 using the CRCI value.

The SRNC 3331 transmits the Eb/No 3332 for outer-loop power control andthe lur control frame 3333 to DRNC 3321. At this point, the SRNC 3331fills the SRNTI value in a payload of the lur control frame beforetransmission, in order to inform the DRNC 3321 of the corresponding UEused for outer-loop power control.

Upon receipt of the lur control frame 3333, the DRNC 3321 analyzes theSRNTI filled in the payload of the lur control frame 3333 and transmitsthe analyzed value to the Node B 3311 to which the corresponding UEbelongs, through a lub control frame 3327 in which Eb/No 3326 isincluded. In this case, the Node B 3311 may add the SRNTI value or thePCPCH indicator to the lub control frame 3327, providing for the casewhere the Node B 3311 cannot distinguish to which UE the received lubcontrol frame 3327 corresponds.

Upon receipt of the lub control frame 3327, the Node B 3311 sets theEb/No value 3316 transmitted from the SRNC as a threshold value forinner-loop power control, and performs inner-loop power control. The“inner-loop power control” refers to closed-loop power control performedonly between the UE and the Node B.

FIG. 34 shows a structure of the lub data frames 3313 and 3315 of FIG.33, wherein QE is the message added for outer-loop power control of theuplink PCPCH according to an embodiment of the present invention.

FIG. 35 shows a structure of the lur data frames 3323 and 3325 of FIG.33, wherein QE and CRCI are the messages added for outer-loop powercontrol of the uplink PCPCH according to an embodiment of the presentinvention.

FIG. 36 shows a structure of the control frame 3333 of FIG. 33, wherein“Payload” is the message added for outer-loop power control of theuplink PCPCH according to an embodiment of the present invention.

FIG. 37 shows a structure of the control frame 3327 of FIG. 33, wherein“Payload” is the message added for outer-loop power control of theuplink PCPCH according to an embodiment of the present invention.

FIG. 20 shows a slot structure of a power control preamble PC_Ptransmitted from the UE to the UTRAN. The PC_P has a length of 0 or 8slots. The length of the PC_P becomes 0 slots, when the radioenvironment between the UTRAN and the UE is so good that it is notnecessary to set initial power of the uplink CPCH or when the systemdoes not use the PC_P. Otherwise, the length of the PC_P becomes 8slots. Shown in FIG. 20 is the fundamental structure of the PC_P definedin the W-CDMA standard. The PC_P has two slot types, and includes 10bits per slot. Reference numeral 2001 of FIG. 20 indicates the pilotfield, which is comprised of 8 or 7 bits according to the slot type ofthe PC_P. Reference numeral 2003 indicates a feedback information fieldused when there is feedback information to be transmitted to the UTRAN,and this field has a length of 0 or 1 bit. Reference numeral 2005indicates a field for transmitting a power control command. This fieldis used when the UE controls transmission power of the downlink, and hasa length of 2 bits.

The UTRAN measures transmission power of the UE using the pilot field2001 and then transmits a power control command over the downlinkdedicated channel established when the uplink CPCH is established, tocontrol initial transmission power of the uplink CPCH. In the powercontrol process, the UTRAN transmits a power-up command when it isdetermined that the transmission power of the UE is low, and transmits apower-down command when it is determined that the transmission power ishigh.

The preferred embodiment of the present invention proposes a method forusing the PC_P for the purpose of confirming CPCH establishment inaddition to the purpose of power control. A reason for confirming CPCHestablishment is as follows. When the UTRAN has transmitted a channelallocation message to the UE, the channel allocation message may have anerror due to a bad radio environment or a bad multi-path environmentbetween the UTRAN and the UE. In this case, the UE will receive thechannel allocation message with errors and wrongly use a CPCH which wasnot designated by the UTRAN, thus causing a collision on the uplink withanother UE using the corresponding CPCH. Such a collision may occur inthe prior art even when the right of using the channel is required, ifthe UE misconceives NAK transmitted from the UTRAN for ACK. Therefore,one preferred embodiment of the present invention proposes a method inwhich the UE requests the UTRAN to confirm the channel message again,thereby increasing the reliability in using the uplink CPCH.

The foregoing method in which the UE requests the UTRAN to confirm thechannel allocation message or channel request message, using the PC_P,does not affect the PC_P's original purpose of measuring receiving powerof the uplink for power control. The pilot field of the PC_P isinformation known to the UTRAN, and a value of the channel allocationconfirmation message transmitted from the UE to the UTRAN is also knownto the UTRAN, so that the UTRAN has no difficulty in measuring thereceiving power of the uplink. Therefore, the UTRAN can confirm whetherthe UE has normally received the channel allocation message, byexamining the receiving status of the PC_P. In this embodiment of thepresent invention, if the pilot bits known to the UTRAN are notdemodulated in the process of measuring the receiving power of theuplink, the UTRAN determines that a channel allocation message or achannel using ACK message transmitted to the UE has an error, andcontinuously transmits a power-down command for decreasing transmissionpower of the uplink over a downlink which corresponds to the uplink CPCHon a one-to-one basis. Since the W-CDMA standard specifies that thepower-down command should be transmitted 16 times for one 10 ms frame,the transmission power decreases by at least 15 dB within 10 ms from thetime point when the error has occurred, not having so serious influenceover the other UEs.

FIG. 21 shows a structure of the PC_P of FIG. 20. Referring to FIG. 21,reference numeral 2101 indicates the PC_P and has the same structure asshown in FIG. 20. Reference numeral 2103 indicates a channelizationcode, which is multiplied by the CP_P by a multiplier 2102 to channelspread the PC_P. The channelization code 2103 has a spreading factor of256 chips, and is set according to a rule determined by a CA messagetransmitted from the UTRAN. Reference numeral 2105 indicates a PC_Pframe, which is comprised of 8 slots, each slot having a length of 2560chips. Reference numeral 2107 indicates an uplink scrambling code usedfor the PC_P. A multiplier 2106 spreads the PC_P frame 2105 with theuplink scrambling code 2107. The spread PC_P frame is transmitted to theUTRAN.

FIG. 22A shows a method for transmitting a channel allocationconfirmation message or a channel request confirmation message from theUE to the UTRAN by using the PC_P. In FIG. 22A, PC_P 2201,channelization code 2203, PC_P frame 2205 and uplink scrambling code2207 have the same structure and operation as the PC_P 2101,channelization code 2103, PC_P frame 2105 and uplink scrambling code2107 of FIG. 21. Further, multipliers 2202 and 2206 also have the sameoperation as the multipliers 2102 and 2106 of FIG. 21, respectively. Totransmit the channel allocation confirmation message or channel requestconfirmation message to the UTRAN using the PC_P, a channel number orsignature number of the CA_ICH received from the UTRAN is repeatedlymultiplied by the pilot field of the PC_P 2201 before transmission.Reference numeral 2209 of FIG. 22A indicates a CPCH confirmation messagewhich includes the signature number used in the CA_ICH transmitted fromthe UTRAN to the UE or the CPCH channel number. Here, the signaturenumber is used for the CPCH confirmation message, when the signaturesused for the CA_ICH correspond to the CPCHs on a one-to-one basis, andthe CPCH channel number is used for the CPCH confirmation message, whena plurality of signatures correspond to one CPCH. The CPCH confirmationmessage 2209 is repeatedly multiplied by the pilot field of the PC_P bya multiplier 2208 before transmission.

FIG. 22B shows structures of the uplink scrambling codes used by aplurality of UEs in the UTRAN for the AP, CD_P, PC_P, and CPCH messagepart when transmitting the PC_P by using the method of FIG. 22A.Reference numeral 2221 of FIG. 22B indicates a scrambling code used forthe AP, which is known to the UEs by the UTRAN over the broadcastingchannel or which is equally used for the AP part in the whole system.The scrambling code 2223 used for the CD_P is a scrambling code whichhas the same initial value as the scrambling code 2221 for the AP buthas a different start point. However, when the signature group used forthe AP is different from the signature group used for the CP_P, the samescrambling code as the scrambling code 2221 for the AP is used for thescrambling code 2223. Reference numeral 2225 indicates a scrambling codeused for the PC_P which is known to the UE by the UTRAN or which isequally used for the PC_P part in the whole system. The scrambling codeused for the PC_P part can be either identical to or different from thescrambling code used for the AP and CP_P part. Reference numerals 2227,2237 and 2247 indicate scrambling codes used when UE#1, UE#2 and UE#k inthe UTRAN transmit the CPCH message parts using CPCHs. The scramblingcodes 2227, 2237 and 2247 can be set according to the APs transmittedfrom the UEs or the CA_ICH messages transmitted from the UTRAN. Here,‘k’ indicates the number of the UEs which can simultaneously use CPCHs,or the number of the CPCHs in the UTRAN.

In FIG. 22B, when the uplink scrambling code used by the UTRAN for theCPCH is not allocated to every CPCH or every UE, the number of thescrambling codes used for the message part may be smaller than thenumber of the UEs which can simultaneously use the CPCHs in the UTRAN orthe number of the CPCHs in the UTRAN.

FIG. 23 shows another method for transmitting the channel allocationconfirmation message or channel request confirmation message transmittedfrom the UE to the UTRAN using the PC_P. In FIG. 23, PC_P 2301,channelization code 2303, PC_P frame 2305 and uplink scrambling code2307 have the same structure and operation as the PC_P 2101,channelization code 2103, PC_P frame 2105 and uplink scrambling code2107 of FIG. 21. Further, multipliers 2302 and 2306 also have the sameoperation as the multipliers 2102 and 2106 of FIG. 21, respectively. Totransmit the channel allocation confirmation message or channel requestconfirmation message to the UTRAN using the PC_P, the PC_P frame 2305 ismultiplied by the CPCH confirmation message 2309 in a chip unit and thenspread with a scrambling code 2307. Here, it is possible to obtain thesame result, even though the sequence of multiplying the CPCHconfirmation message and the scrambling code by the PC_P frame isreversed. The CPCH confirmation message includes the signature numberused in the CA_ICH transmitted from the UTRAN to the UE or the CPCHchannel number. Here, the signature number is used for the CPCHconfirmation message, when the signatures used for the CA_ICH correspondto the CPCHs on a one-to-one basis, and the CPCH channel number is usedfor the CPCH confirmation message, when a plurality of signaturescorrespond to one CPCH. The environments in which the UEs in the UTRANuse the scrambling codes in the method of FIG. 23 are equal to theenvironments given in the method of FIGS. 22A and 22B.

FIG. 24A shows another method for transmitting the channel allocationconfirmation message or channel request confirmation message from the UEto the UTRAN using the PC_P. In FIG. 24A, PC_P 2401, PC_P frame 2405 anduplink scrambling code 2407 have the same structure and operation as thePC_P 2101, PC_P frame 2105 and uplink scrambling code 2107 of FIG. 21.Further, multipliers 2402 and 2306 also have the same operation as themultipliers 2102 and 2106 of FIG. 21, respectively. To transmit thechannel allocation confirmation message or channel request confirmationmessage to the UTRAN using the PC_P, a channelization code 2403 isassociated with the CA_ICH signature received at the UE from the UTRANor the CPCH channel number on a one-to-one basis to channel spread thePC_P using the channelization code and transmit the channel-spread PC_Pto the UTRAN. The environments in which the UEs in the UTRAN use thescrambling codes in the method of FIG. 24A are equal to the environmentsgiven in the method of FIG. 22B.

FIG. 24B shows an example of a PC_P channel code tree which correspondto the CA_ICH signatures or the CPCH channel numbers on a one-to-onebasis. This channel code tree is called an OVSF (Orthogonal VariableSpreading Factor) code tree in the W-CDMA standard, and the OVSF codetree defines orthogonal codes according to the spreading factors. In theOVSF code tree 2431 of FIG. 24B, a channelization code 2433 used as aPC_P channelization code has a fixed spreading factor of 256, and thereare several possible mapping rules for associating the PC_Pchannelization code with the CA_ICH signatures or the CPCH channelnumbers on a one-to-one basis. As an example of the mapping rule, thelowest one of the channelization codes having the spreading factor 256can be associated with the CA_ICH signature or CPCH channel number on aone-to-one basis; and the highest channelization code can also beassociated with the CA_ICH signature or the CPCH channel number on aone-to-one basis, by changing the channelization code or skippingseveral channelization codes. In FIG. 24B, ‘n’ may be the number of theCA_ICH signatures or the number of the CPCH channels.

FIG. 25A shows another method for transmitting a channel allocationconfirmation message or a channel request confirmation messagetransmitted from the UE to the UTRAN using the PC_P. In FIG. 25A, PC_P2501, channelization code 2503 and PC_P frame 2505 have the samestructure and operation as the PC_P 2101, channelization code 2103 andPC_P frame 2105 of FIG. 21. Further, multipliers 2502 and 2506 also havethe same operation as the multipliers 2102 and 2106 of FIG. 21,respectively. To transmit the channel allocation confirmation message orchannel request confirmation message to the UTRAN using the PC_P, anuplink scrambling code 2507 is associated with the channel number ofsignature number of the CA_ICH received from the UTRAN on a one-to-onebasis to channel spread the PC_P frame 2505 with the uplink scramblingcode before transmission. Receiving the PC_P frame transmitted from theUE, the UTRAN determines whether the scrambling code used for the PC_Pframe corresponds to the signature or CPCH channel number transmittedover the CA_ICH on a one-to-one basis. If the scrambling code does notcorrespond to the signature or CPCH channel number, the UTRANimmediately transmits a power-down command for decreasing transmissionpower of the uplink to the power control command field of the downlinkdedicated channel corresponding to the uplink CPCH on a one-to-onebasis.

FIG. 25B shows the structures of uplink scrambling codes used for theAP, CD_P, PC_P and CPCH message part by a plurality of UEs in the UTRANwhen transmitting the PC_P using the method of FIG. 25A. Referencenumeral 2521 of FIG. 25B indicates a scrambling code used for the AP,which is known to the UEs by the UTRAN over the broadcasting channel orwhich is equally used for the AP part in the whole system. For ascrambling code 2523 used for the CD_P, is used a scrambling code whichhas the same initial value as the scrambling code 2521 for the AP buthas a different start point. However, when the signature group used forthe AP is different from the signature group used for the CP_P, the samescrambling code as the scrambling code 2521 for the PA is used for thescrambling code 2523. Reference numerals 2525, 2535 and 2545 indicatescrambling codes used when UE#1, UE#2 and UE#k transmit the PC_P, andthese scrambling codes correspond to the signature or CPCH channelnumber of the CA_ICH received at the UE from the UTRAN on a one-to-onebasis. With regard to the scrambling codes, the UE can store thescrambling code used for the PC_P or the scrambling code can be known tothe UE by the UTRAN. The PC_P scrambling codes 2525, 2535 and 2545 maybe identical to the scrambling codes 2527, 2537 and 2547 used for theCPCH message part, or may be scrambling codes corresponding to them on aone-to-one basis. In FIG. 25B, ‘k’ indicates the number of CPCHs in theUTRAN.

FIGS. 26A to 26C show the procedure for allocating the CPCH channel inthe UE according to an embodiment of the present invention, and FIGS.27A to 27C show the procedure for allocating the CPCH channel in theUTRAN according to an embodiment of the present invention.

Referring to FIG. 26A, the UE generates data to be transmitted over theCPCH in step 2601, and acquires information about a possible maximumdata rate by monitoring the CSICH in step 2602. The information whichcan be transmitted over the CSICH in step 2602 may include informationabout whether the data rates supported by the CPCH can be used. Afteracquiring the CPCH information of the UTRAN in step 2602, the UE selectsa proper ASC based on the information acquired over the CSICH and theproperty of transmission data, and randomly selects a valid CPCH_APsub-channel group in the selected ASC, in step 2603. Thereafter, in step2604, the UE selects a valid access slot from the frames of SFN+1 andSFN+2 using the SFN of the downlink frame and the sub-channel groupnumber of the CPCH. After selecting the access slot, the UE selects asignature appropriate for the data rate at which the UE will transmitthe data, in step 2605. Here, the UE selects the signature by selectingone of the signatures for transmitting the information. Thereafter, theUE performs desired transport format (TF) selection, persistence checkand accurate initial delay for AP transmission in step 2606, setsrepetitive transmission number and initial transmission power of the APin step 2607, and transmits the AP in step 2608. After transmitting theAP, the UE awaits ACK in response to the transmitted AP in step 2609. Itis possible to determine whether ACK has been received or not, byanalyzing the AP_AICH transmitted from the UTRAN. Upon failure toreceive ACK in step 2609, the UE determines in step 2631 whether the APrepetitive transmission number set in step 2607 has been exceeded. Ifthe set AP repetitive transmission number has been exceeded in step2631, the UE transmits an error occurrence system response to the upperlayer to stop the CPCH access process and to perform an error recoveryprocess in step 2632. Whether the AP repetitive transmission number hasbeen exceeded or not can be determined using a timer. However, if the APrepetitive transmission number has not been exceeded in step 2631, theUE selects a new access slot defined in the CPCH_AP sub-channel group instep 2633, and selects a signature to be used for the AP in step 2634.In selecting the signature in step 2634, the UE selects a new signatureout of the valid signatures in the ASC selected in step 2603 or selectsthe signature selected in step 2605. Thereafter, the UE resetstransmission power of the AP in step 2635, and repeatedly performs thestep 2608.

Upon receipt of ACK in step 2609, the UE selects a signature to be usedfor the CD_P from the signature group for the preamble and selects anaccess slot for transmitting the CD_P in step 2610. The access slot fortransmitting the CD_P may indicate a given time point after the UE hasreceived ACK, or a fixed time point. After selecting the signature andaccess slot for the CD_P, the UE transmits the CD_P which uses theselected signature at the selected access slot, in step 2611.

After transmitting the CD_P, the UE determines in step 2612 of FIG. 26Bwhether ACK for CD_P and a channel allocation message are received. TheUE performs different operation according to whether an ACK has beenreceived or not over the CD_ICH. In step 2612, the UE can determine areceived time of an ACK for the CD_P and the channel allocation messageby using a timer. If an ACK is not received within a time set by thetimer or a NAK for the transmitted CD_P is received in step 2612, the UEproceeds to step 2641 to stop the CPCH access procedure. In step 2641,the UE transmits an error occurrence system response to the upper layerto stop the CPCH access procedure and perform an error recovery process.However, if an ACK for the CD_P is received in step 2612, the UEanalyzes the channel allocation message in step 2613. It is possible tosimultaneously detect and analyze ACK for the CD_P and the channelallocation message by using the AICH receivers of FIGS. 16 and 17.

The UE determines, in step 2614, an uplink scrambling code and an uplinkchannelization code for a message part of a physical common packetchannel (PCPCH) according to the channel allocation message analyzed instep 2613, and determines a channelization code for a downlink dedicatedchannel established for power control of the CPCH. Thereafter, the UEdetermines in step 2615 whether the slot number of power controlpreamble PC_P is 8 or 0. If the number of the PC_P slots is 0 in step2615, the UE performs step 2619 to start receiving the downlinkdedicated channel transmitted from the UTRAN; otherwise, if the numberof the PC_P slots is 8, the UE performs step 2617. In step 2617, the UEformats the power control preamble PC_P according to the uplinkscrambling code, the uplink channelization code and the slot type to beused for the PC_P. The PC_P has 2 slot types. After selecting thescrambling code for the PC_P and the channelization code, the UEtransmits the PC_P in step 2618, and at the same time, receives thedownlink dedicated channel to perform transmission power control of theuplink and reception power control of the downlink. Thereafter, in step2620, the UE formats the PCPCH message part according to the channelallocation message analyzed in step 2613, and starts transmission of theCPCH message part in step 2621.

Thereafter, the UE determines in step 2622 of FIG. 26C whether the PC_Pis transmitted in an acknowledgement mode for acknowledging channelallocation. If the PC_P is not transmitted in the acknowledgement modein step 2622, the UE performs step 2625 after transmission of the CPCHmessage part, to transmit a CPCH transmission stop status response tothe upper layer, and ends the process of transmitting the data over theCPCH in step 2626. However, if the PC_P is transmitted in theacknowledgement mode in step 2622, the UE sets a timer for receiving anACK of the CPCH message part in step 2623, and monitors a forward accesschannel (FACH) during and after transmission of the CPCH message part instep 2624, to determine whether an ACK or NAK for the CPCH message parthas been received from the UTRAN. It is possible to use a downlinkdedicated channel as well as the FACH in receiving an ACK or NAK fromthe UTRAN. Upon failure to receive an ACK for the CPCH message part overthe FACH in step 2624, the UE determines in step 2651 whether the timerset in step 2623 has expired or not. If the timer has not expired, theUE returns to step 2624 to monitor for an ACK or NAK from the UTRAN.However, if the timer has expired, the UE transmits a transmission failstatus response to the upper layer and performs an error recoveryprocess in step 2652. However, if an ACK has been received in step 2624,the UE performs steps 2625 and 2626, completing transmission of theCPCH.

Now, a detailed description will be made regarding how the UTRANallocates the CPCH, with reference to FIGS. 27A to 27C.

The UTRAN transmits information about the maximum data rate supported bythe CPCH or information as to whether the CPCH is available according tothe data rates, using the CSICH, in step 2701 of FIG. 27A. The UTRANmonitors an access slot to receive an AP transmitted from the UEs instep 2702. While monitoring the access slot, the UTRAN determines instep 2703 whether an AP has been detected. Upon failure to detect an APin step 2703, the UTRAN returns to step 2702 and repeats the aboveprocess. Otherwise, upon detection of the AP in step 2703, the UTRANdetermines in step 2704 whether two or more APs have been detected (orreceived). If two or more APs have been detected in step 2704, the UTRANselects a proper one of the detected APs in step 2731 and then proceedsto step 2705. Otherwise, if one only AP has been received and it isdetermined that receiving power of the received AP or a requirement forthe CPCH included in the signature for the received AP is appropriate,the UTRAN performs step 2705. Here, the “requirement” refers to a datarate that the UE desires to use for the CPCH or the number of dataframes to be transmitted by the user, or a combination of the tworequirements.

If one AP has been detected in step 2704 or after selecting a proper APin step 2731, the UTRAN proceeds to step 2705 to generate an AP_AICH fortransmitting an ACK for the detected or selected AP, and then transmitsthe generated AP_AICH in step 2706. After transmitting the AP_AICH, theUTRAN monitors an access slot to receive the CD_P transmitted from theUE that has transmitted the AP, in step 2707. It is possible to receivethe AP, even in the process of receiving the CD_P and monitoring theaccess slot. That is, the UTRAN can detect the AP, CD_P and PC_P fromthe access slots, and generate the AICHs for the detected preambles.Therefore, the UTRAN can simultaneously receive the CD_P and the AP. Inthis embodiment of the present invention, the description will be madefocusing on the process in which the UTRAN detects the AP generated by agiven UE and then allocates the CPCH as shown in FIG. 3. Therefore, thedescription of the operation performed by the UTRAN will be made in thesequence of a response, made by the UTRAN, to the AP transmitted from agiven UE, a response to the CD_P transmitted from the UE that hastransmitted the AP, and a response to the PC_P transmitted from thecorresponding UE. Upon detecting the CD_P in step 2708, the UTRANperforms step 2709; otherwise, upon failure to detect the CD_P, theUTRAN performs the step 2707 to monitor detection of the CD_P. The UTRANhas two monitoring methods: one method is to use a timer if the UEtransmits the CD_P at a fixed time after the AP_AICH, another method isto use a searcher if the UE transmits the CD_P at a given time. Upondetecting the CD_P in step 2708, the UTRAN determines in step 2709whether two or more CD_Ps have been detected. If two or more CD_Ps havebeen detected in step 2709, the UTRAN selects a proper one of thereceived CD_Ps in step 2741, and generates the CD_ICH and the channelallocation message in step 2710. In step 2741, the UTRAN may select theproper CD_P depending on the receiving power of the received CD_Ps. Ifone CD_P has been received in step 2709, the UTRAN proceeds to step 2710where the UTRAN generates a channel allocation message to be transmittedto the UE that has transmitted the CD_P selected in step 2741 or theCD_P received in step 2709.

Thereafter, in step 2711 on FIG. 27B, the UTRAN generates ACK for theCD_P detected in step 2708 and the CD/CA_ICH for transmitting thechannel allocation message generated in step 2710. The UTRAN maygenerate the CD/CA_ICH in the method described with reference to FIGS.13A and 13B. The UTRAN transmits the generated CD/CA_ICH in step 2712 inthe method described with reference to FIGS. 14 and 15. Aftertransmitting the CD/CA_ICH, the UTRAN generates a downlink dedicatedchannel (DL_DPCH) for controlling transmission power of the uplink CPCHin step 2713. the generated downlink dedicated channel corresponds tothe uplink CPCH transmitted from the UE on a one-to-one basis. The UTRANtransmits information for controlling transmission power of the PCPCH instep 2714, using the DL_DPCH generated in step 2713. The UTRAN examinesthe slot or timing information by receiving the PC_P transmitted fromthe UE, in step 2715. If the slot number or timing information of thePC_P transmitted from the UE is ‘0’ in step 2715, the UTRAN startsreceiving a message part of the PCPCH transmitted from the UE in step2719. Otherwise, if the slot number or timing information of the PC_Ptransmitted from the UE is ‘8’ in step 2715, the UTRAN proceeds to step2716 where the UTRAN receives the PC_P transmitted from the UE andcreates a power control command for controlling transmission power ofthe PC_P. One object of controlling transmission power of the PC_P is toproperly control initial transmission power of the uplink PCPCHtransmitted from the UE. The UTRAN transmits the power control commandgenerated in step 2716 through a power control command field of adownlink dedicated physical control channel (DL_DPCCH) out of thedownlink dedicated channels generated in step 2713. Thereafter, theUTRAN determines in step 2718 whether the PC_P has been completelyreceived. If reception of the PC_P is not completed, the UTRAN returnsto step 2717; otherwise, if reception of the PC_P is completed, theUTRAN performs step 2719. Whether reception of the PC_P is completed ornot can be determined by using a timer to examine whether 8 PC_P slotshave arrived. If it is determined in step 2718 that reception of thePC_P is completed, the UTRAN starts receiving a message part of theuplink PCPCH in step 2719, and determines in step 2720 whether receptionof the PCPCH message part is completed. If reception of the PCPCHmessage part is not completed, the UTRAN continuously receives thePCPCH, and otherwise, if reception of the PCPCH is completed, the UTRANproceeds to step 2721 of FIG. 27C.

The UTRAN determines in step 2721 whether the UE transmits the PCPCH inan acknowledgement transmission mode. If the UE transmits the PCPCH inan acknowledgement transmission mode, the UTRAN performs step 2722, andotherwise, performs step 2724 to end reception of the CPCH. If it isdetermined in step 2721 that the UE transmits the PCPCH in theacknowledgement transmission mode, the UTRAN determines in step 2722whether the received PCPCH message part has an error. If the receivedPCPCH message part has an error, the UTRAN transmits NAK through aforward access channel (FACH) in step 2751. Otherwise, if the receivedPCPCH message part has no error, the UTRAN transmits ACK through theFACH in step 2723 and then ends reception of the CPCH in step 2724.

FIGS. 28A and 28B show the procedure for allocating the CPCH in the UEaccording to another embodiment of the present invention, wherein“START” of FIG. 28A is connected to “A” of FIG. 26A. FIGS. 29A to 29Cshow the procedure for allocating the CPCH in the UTRAN according toanother embodiment of the present invention, wherein “START” of FIG. 29Ais connected to “A” of FIG. 27A. FIGS. 28A–28B and FIGS. 29A–29C showthe methods for establishing the stable CPCH using the PC_P describedwith reference to FIGS. 22 to 26, performed by the UE and the UTRAN,respectively.

Referring to FIG. 28A, the UE determines in step 2801 whether CD_ICH andCA_ICH have been received from the UTRAN. Upon failure to receive theCD/CA_ICH in step 2801, the UE transmits an error occurrence systemresponse to the upper layer to end the CPCH access procedure and theerror recovery process in step 2821. “Failure to receive the CD/CA_ICH”includes one case where an ACK is not received although the CD/CA_ICH isreceived, and another case where the CD/CA_ICH is not received from theUTRAN within a predetermined time. The “predetermined time” refers to atime previously set when starting the CPCH access procedure, and a timercan be used in setting the time.

Otherwise, if it is determined in step 2801 that the CD/CA_ICH have beenreceived and ACK is detected from the CD_ICH, the UE analyzes thechannel allocation message transmitted from the UTRAN in step 2802.After analyzing the channel allocation message in step 2802, the UEproceeds to step 2803 where the UE determines an uplink scrambling codeof the PCPCH message part, an uplink channelization code, and achannelization code for the downlink channel used for controlling theuplink CPCH according to the analyzed channel allocation message.

Thereafter, in step 2804, the UE constructs the PC_P according to theslot type using the uplink scrambling code and the uplink channelizationcode set in step 2803. This embodiment of the present inventionincreases stability and reliability of the CPCH using the PC_P. It isassumed that the length or timing information of the PC_P slot is alwaysset to 8 slots.

In step 2805, the UE inserts a channel allocation confirmation messagein the PC_P in order to verify the channel allocation message receivedfrom the UTRAN. The UE can insert the channel allocation confirmationmessage in the PC_P in the methods described with reference to FIGS. 22to 25. In the method of FIG. 22, a pilot bit of the PC_P is multipliedby the channel allocation message or the signature number received atthe UE before transmission. In the method of FIG. 23, the PC_P slot ismultiplied by the channel allocation message or the signature numberreceived at the UE by the chip level before transmission. In the methodof FIG. 24, the PC_P is channelized with a channelization codecorresponding to the channel allocation message or the signature numberreceived at the UE before transmission. In the method of FIGS. 25A and25B, the PC_P is spread with a scrambling code corresponding to thechannel allocation message or the signature received at the UE and thentransmitted to the UTRAN. When transmitting the channel allocationmessage using the multiple signatures, the UTRAN uses the channelallocation message for the CPCH allocated to the UE. When allocating theCPCH using one signature, the UTRAN uses the signature for the channelallocation message.

Thereafter, in step 2806, the UE transmits the PC_P generated in step2805 to the UTRAN, and starts receiving the DL_DPCH transmitted from theUTRAN in step 2807. In addition, the UE measures receiving power of thedownlink using the pilot field of the DL_DPCH and inserts a command forcontrolling transmission power of the downlink in a power controlcommand part of the PC_P according the measured receiving power.

While transmitting the PC_P to the UTRAN and receiving the DL_DPCH, theUE determines in step 2808 whether an error signal for the channelallocation message analyzed by the UE or a specific PCB (Power ControlBit) pattern requiring release of the CPCH has been received from theUTRAN. If it is determined in step 2808 that the analyzed channelallocation message has an error or the PCB pattern indicates a CPCHrelease, the UE ends transmission of the PC_P in step 2831 and transmitsa PCPCH transmission stop status response to the upper layer andperforms the error recovery process, in step 2832.

However, if it is determined in step 2808 that the error signal for thechannel allocation message or the specific PCB pattern is not receivedfrom the UTRAN, the UE constructs the PCPCH message part according tothe analyzed channel allocation message in step 2809.

Continuing at step 2810 of FIG. 28B, the UE starts transmitting thePCPCH message part generated in step 2809. While transmitting the PCPCHmessage part, the UE performs step 2811 which is identical to step 2808of FIG. 28A. Upon receipt of an error confirmation message for thechannel assignment message or a channel release request message from theUTRAN in step 2811, the UE performs steps 2841 and 2842. The UE stopstransmission of the PCPCH message part in step 2841, and transmits aPCPCH transmission stop status response to the upper layer and performsthe error recovery process in step 2842. The channel release requestmessage has two different types. The first type of channel releaserequest message is transmitted when the UTRAN knows, after startingtransmission of the PCPCH, that the presently established CPCH hascollided with a CPCH of another UE due to the delay in confirming thechannel allocation message for the presently established CPCH,transmitted from the UTRAN. The second type of channel release requestmessage is transmitted when the UTRAN transmits a collision messageindicating a collision with another user to a first UE which correctlyuses the CPCH and a second UE starts transmission using the CPCH overwhich the first UE is presently communicating with the UTRAN, becausethe channel allocation message received at the second UE using the CPCHfrom the UTRAN has an error. At any rate, upon receipt of the channelrelease message, the UTRAN command both the first UE which correctlyuses the CPCH and the second UE which has received the channelallocation message with an error to stop using the uplink CPCH.

However, if the error signal for the channel allocation message or thespecific PCB pattern for requesting channel release from the UTRAN isnot received from the UTRAN in step 2811, the UE continuously transmitsthe PCPCH message part in step 2812, and determines in step 2813 whethertransmission of the PCPCH message part is completed. If transmission ofthe PCPCH message part is not completed, the UE returns to step 2812 tocontinue performing the above operation. Otherwise, if transmission ofthe PCPCH message part is completed, the UE performs operation of step2814.

The UE determines in step 2814 whether transmission is made in theacknowledgement mode. If transmission is not made in the acknowledgementmode, the UE ends transmission of the PCPCH message part and performsstep 2817 where the UE transmits a PCPCH transmission stop statusresponse to the upper layer and ends the CPCH data transmission process.However, if transmission is made in the acknowledgement mode, the UEsets a timer for receiving ACK of the CPCH message part in step 2815.Thereafter, in step 2816, the UE monitors the forward access channel(FACH) during and after transmission of the CPCH message part, todetermine whether an ACK or NAK for the CPCH message part has beenreceived from the UTRAN. The UTRAN can transmit an ACK or NAK throughthe downlink channel as well as the FACH. If an ACK for the CPCH messagepart is not received through the FACH in step 2816, the UE determines instep 2851 whether the timer set in step 2815 has expired or not. If thetimer has not expired yet in step 2815, the UE returns to step 2816 andmonitors for an ACK or NAK transmitted from the UTRAN. Otherwise, if thetimer has expired in step 2815, the UE transmits a PCPCH transmissionfail status response to the upper layer and performs the error recoveryprocess, in step 2852. However, upon receipt of ACK in step 2816, the UEperforms step 2817 and ends transmission of the CPCH.

Now, a description of the UTRAN will be made with reference to FIGS. 29Ato 29C, wherein “START” of FIG. 29A is connected to “A” of FIG. 27A.

In step 2901 of FIG. 29A, the UTRAN generates the CD/CA_ICH fortransmitting ACK for the CD_P detected in step 2708 of FIG. 27A and thechannel allocation message generated in step 2710. The CD/CA_ICH can begenerated in the method described with reference to FIGS. 13A and 13B.In step 2902, the UTRAN transmits the CA/CD_ICH generated in step 2901,in the methods described with reference to FIGS. 14 and 15. Aftertransmitting the CD/CA_ICH, the UTRAN generates a downlink dedicatedchannel for controlling transmission power of the uplink CPCH. Thegenerated downlink dedicated channel corresponds to the uplink CPCHtransmitted from the UE on a one-to-one basis. The UTRAN transmits theDL_DPCH generated in step 2903, in step 2904, and receives the PC_Ptransmitted from the UE and analyzes a confirmation message for thereceived channel allocation message in step 2905. The UTRAN determinesin step 2906 whether the channel allocation conformation messagetransmitted from the UE is identical to the channel allocation messagetransmitted by the UTRAN, based on the results analyzed in the step2905. If they are identical in step 2906, the UTRAN performs step 2907,and otherwise, proceeds to step 2921. The UE can transmit the channelallocation message to the UTRAN using the PC_P in the methods describedwith reference to FIGS. 22 to 25. In the method of FIG. 22, a pilot bitof the PC_P is multiplied by the channel allocation message or thesignature number received at the UE before transmission. In the methodof FIG. 23, the PC_P slot is multiplied by the channel allocationmessage or the signature number received at the UE by the chip levelbefore transmission. In the method of FIG. 24, the PC_P is channelizedwith a channelization code corresponding to the channel allocationmessage or the signature number received at the UE before transmission.In the method of FIG. 25, the PC_P is spread with a scrambling codecorresponding to the channel allocation message or the signaturereceived at the UE and then transmitted to the UTRAN. When transmittingthe channel allocation message using the multi-signature, the UTRAN usesthe channel allocation message for the CPCH allocated to the UE. Whenallocating the CPCH using one signature, the UTRAN uses the signaturefor the channel allocation message.

The UTRAN determines in step 2921 of FIG. 29B whether a CPCHcorresponding to the channel allocation confirmation message received instep 2905 is used by another UE. If it is determined in step 2921 thatthe CPCH is not used by another UE, the UTRAN performs step 2925 wherethe UTRAN transmits a PCPCH transmission stop status response to theupper link and performs the error recovery process. The “error recoveryprocess” performed by the UTRAN refers to ordering the UE to stoptransmission of the CPCH by transmitting a CPCH transmission stopmessage to the UE through the downlink dedicated channel in use,transmitting the CPCH transmission stop message to the UE through theFACH, or continuously transmitting a specific bit pattern previouslyappointed with the UE. In addition, the error recovery process mayinclude a method in which the UTRAN continuously transmits a command fordecreasing transmission power of the uplink through the DL_DPCH receivedat the UE.

If it is determined in step 2921 that the CPCH corresponding to thechannel allocation confirmation message received in step 2905 is used byanother UE, the UTRAN transmits a power-down command through the DL_DPCHwhich is commonly used by the two UEs, in step 2922. Thereafter, in step2923, the UTRAN releases the channel by transmitting the channel releasemessage or the specific PCB pattern to the two UEs through the FACH. TheUTRAN may use the downlink dedicated channel as well as the FACH, whentransmitting the channel release message or the specific PCB pattern.After step 2923, the UTRAN stops transmitting the DL_DPCH to the UE instep 2924, and ends reception of the CPCH in step 2925.

Otherwise, if the channel confirmation message received from the UE instep 2906 is consistent with the channel allocation message allocated bythe UTRAN, the UTRAN performs step 2907 where the UTRAN receives thePC_P transmitted from the UE and generates a power control command forcontrolling transmission power of the PC_P. One object of controllingtransmission power of the PC_P is to properly control initialtransmission power of the uplink PCPCH transmitted from the UE. In step2908, the UTRAN transmits the generated power control command through apower control command field of the downlink dedicated physical controlchannel (DL_DPCCH) out of the downlink dedicated channels generated instep 2903. The UTRAN determines in step 2909 whether reception of thePC_P is completed. If reception of the PC_P is not completed, the UTRANreturns to step 2908, and otherwise, proceeds to step 2910. Whetherreception of the PC_P is completed can be determined by using a timer toexamine whether the 8 PC_P slots have all been received. If reception ofthe PC_P is completed in step 2909, the UTRAN starts receiving themessage part of the uplink PCPCH in step 2910, and determines in step2911 whether reception of the message part of the uplink PCPCH. Ifreception of the PCPCH message part is not completed, the UTRANcontinuously receives the PCPCH. If reception of the PCPCH message partis completed, the UTRAN determines in step 2921 of FIG. 29C whether theUE has transmitted the PCPCH in the acknowledgement transmission mode.If the UE has transmitted the PCPCH in the acknowledgement transmissionmode, the UTRAN performs step 2931, and if the UE has transmitted thePCPCH not in the acknowledgement transmission mode, the UTRAN performsstep 2915.

If the UE has transmitted the PCPCH in the acknowledgement transmissionmode in step 2912, the UTRAN determines in step 2913 whether the messagepart of the received PCPCH has an error. If the received PCPCH messagepart has an error, the UTRAN transmits NAK through the FACH in step2931. If the received PCPCH message part has no error, the UTRANtransmits an ACK through the FACH in step 2914 and ends reception of theCPCH in step 2915.

FIG. 32 shows an operation performed by a MAC (Medium Access Control)layer of the UE according to an embodiment of the present invention.Upon receipt of MAC-Data-REQ primitive from RLC (Radio Link Control) instep 3201, the MAC layer sets to ‘0’ a parameter M needed to count apreamble romping cycle and a parameter FCT (Frame Counter Transmitted)needed to count the number of transmitted frames, in step 3203. The“preamble romping cycle” refers to a time period in which how many timesthe access preamble can be transmitted. In step 3203, the MAC layeracquires a parameter needed to transmit the CPCH from RRC (RadioResource Control). The parameter may include persistency value P, NFmax,and back-off (BO) time for the respective data rates. The MAC layerincreases the preamble romping cycle counter M in step 3204, andcompares the value M with NFmax acquired from the RRC in step 3205. IfM>NFmax, the MAC layer ends the CPCH acquiring process and performs anerror correction process in step 3241. The error correcting process canbe a process for transmitting a CPCH acquisition fail message to theupper layer of the MAC layer. Otherwise, if M≦NFmax in step 3205, theMAC layer transmits a PHY-CPCH_Status-REQ primitive in step 3206, inorder to acquire information about the PCPCH channels in the presentUTRAN. The information about the PCPCH channels in the UTRAN, requestedin step 3206 by the MAC layer, can be acquired in step 3207. Theacquired PCPCH information in the UTRAN may include an availability ofthe respective channels, a data rate supported by the UTRAN for therespective PCPCHs, multi-code transmit information, and the maximumavailable data rate which can be presently allocated by the UTRAN.

In step 3208, the MAC layer compares the maximum available data rate ofthe PCPCH acquired in step 3207 with a requested data rate to determinewhether the requested data rate is acceptable. If it is an acceptabledata rate, the MAC layer proceeds to step 3209. Otherwise, if it is notan acceptable data rate, the MAC layer waits for an expiry time T untilthe next TTI in step 3231 and then repeats the step 3203 and itssucceeding steps.

The step 3209 is performed when the data rate of the PCPCH desired bythe MAC layer is coincident with the data rate of the PCPCHs in thepresent UTRAN, and in the step 3209, the MAC layer selects a desiredtransport format (TF) for transmitting the CPCH. In order to perform apersistency test to determine whether to attempt an access to the PCPCHsupporting the TF selected in step 3209, the MAC layer draws a randomnumber R in step 3210. Thereafter, in step 3211, the MAC layer comparesthe random number R drawn in step 3210 with the persistency value Pacquired in step 3203 from RRC. If R≦P, the MAC layer proceeds to step3212, and if R>P, the MAC layer returns to step 3231. Alternatively, ifR>P in step 3211, the MAC layer can also perform the following process.That is, the MAC layer includes a busy table for recording availabilityof the respective TFs, records the persistency test-failed TF in thebusy table and then performs again the process from the step 3209. Inthis case, however, the MAC layer consults the busy table in step 3209,in order to select the TF which is not recoded as “busy”.

The MAC layer accurately performs initial delay in step 3212, andtransmits to the physical layer a PHY_Access_REQ (Physical AccessRequest) primitive for commanding the physical layer to perform aprocedure for transmitting the access preamble in step 3213. Reference3214 indicates a process performed after receiving PHY_Access_CNF(Physical Layer Access Confirmation) for the PHY_Access_REQ primitivetransmitted by the MAC layer in step 3213. “A” of step 3214 indicates acase where the MAC layer has received no response over the AP_AICH, andin this case (i.e., upon failure to receive the AP_AICH), the MAC layerperforms again the process from the step 3231. “B” of step 3214indicates a case where the physical layer having received the AP_AICHhas failed to receive a response over the CD/CA_ICH after transmittingthe CD_P. At this point, the MAC layer performs the process from thestep 3231, as in the case “A”. “D” of step 3214 indicates a case wherethe physical layer of the UE has received a NAK from the UTRAN over theAP_AICH. In this case, the MAC layer waits the expiry timer T until thenext TTI in step 3271 and thereafter, waits a back-off time TBOC2 neededwhen the NAK is receive over the AP_AICH, in step 3273, and thenperforms the process again from the step 3203. “E” of step 3214indicates a case where the physical layer of the UE has received thesignature transmitted over the CD/CA_ICH by the UE itself and anothersignature. In this case, the MAC layer waits the expiry timer T untilthe next TTI in step 3251, and thereafter, waits a back-off time TBOC1given when the signature transmitted over the CD/CA_ICH by the UE itselfand another signature are receive, in step 3253, and then performs theprocess again from the step 3203.

“C” of step 3214 indicates a case where the physical layer of the UEinforms the MAC that an ACK for the CD_ICH and the channel allocationmessage have been received over the CA_ICH. In this case, the MAC layerof the UE selects an appropriate TF and builds a transport block setappropriate for the selected TF in step 3215.

In step 3216, the MAC layer of the UE transmits the built transportblock set using a PHY-DATA-REQ primitive. In step 3217, the MAC layer ofthe UE decreases FCT by the number of the frames corresponding to oneTTI and then ends the process for transmitting data over the CPCH instep 3218.

Meanwhile, in order to efficiently transmit packet data using the commonchannel such as the CPCH channel, a scheduling method for effectivelyassigning and releasing the channel is required. The scheduling methodis used to rapidly release the channel when there is no data on a givenuplink channel, and then assign the released channel to another UE,thereby to prevent unnecessary channel access by the UE and a waste ofthe channel resources. For the scheduling, the UE needs to inform theUTRAN that data transmission through the CPCH is ended, if datatransmission is ended before the expiration of NF_max.

To indicate the end of data transmission, the UE needs to perform aspecific operation previously appointed with the UTRAN or to transmit acorresponding specific frame. Upon receipt of the specific frame fromthe UE, the UTRAN releases the assigned CPCH, releases a Node Bresource, and then assigns the channel to another UE requiring the CPCHon judgment that the present CPCH is ended, thereby making it possibleto perform effective scheduling.

FIG. 38 shows a frame structure used when the UE informs the UTRAN of anend of data transmission, according to an embodiment of the presentinvention.

With reference to FIG. 38, a description will be made of an operation inwhich the UE indicates an end of data transmission by inserting aspecific bit in a transmission frame. In FIG. 38, a 1-bit EOF (End ofFrame) field can be added in the physical layer or the upper layer (MACor RLC layer). The EOF bit is set when there is no more data in thetransmission buffer of the UE, i.e., when the last frame is transmitted.For example, when the frames other the last frame are transmitted, theUE sets the EOF bit to ‘0’ to inform the UTRAN that there exists asucceeding frame. Otherwise, when the last frame is transmitted, the UEsets the EOF bit to ‘1’ to inform the UTRAN that the presentlytransmitted frame is the last frame. Meanwhile, when the EOF bit (i.e.,EOF field) is set to ‘1’, the UTRAN releases the CPCH channeldetermining that data transmission is ended.

However, when there occurs an error in a part where the EOF field is setto ‘1’ or when the EOF field is not correctly transmitted to the UTRANdue to a bad air condition (i.e., bad radio condition), the UTRAN cannotrelease the CPCH. To solve this problem, the UTRAN includes a counterfor counting CRC errors, releases the CPCH when the error count valueexceeds a predetermined value, and then stops transmission of powercontrol bits. When the counter value is higher than NF_MAX, the UTRANreleases the CPCH after expiration of NF_MAX. On the contrary, however,when there occurs an error in a frame where the EOF field is set to ‘0’,the UTRAN releases the CPCH and then stops transmission of the powercontrol bits. To solve this problem, the UE creates a null frame andtransmits the null frame with the EOF field set to ‘1’, whentransmitting a frame with the EOF field set to ‘1’. Therefore, since theUTRAN must receive two consecutive frames with their EOF fields set to‘1’ in order to release the CPCH, it is possible to prevent unwantedrelease of the channel due to an error of the EOF field.

FIG. 39 shows a method for releasing the CPCH according to an embodimentof the present invention. In this method, the UE provides the UTRAN withinformation about a length of the transmission data, and the UTRANcompares the number of transmission frames determined according to thedata length with NF_MAX, and ends the CPCH if the number of thetransmission frames is smaller than NF_MAX.

With reference to FIG. 39, a description will be made of the CPCHreleasing method according to an embodiment of the present invention.

The UE sets the total number of transmission frames in a first framebeing transmitted over the CPCH and transmits the set first frame to theUTRAN in order to inform the UTRAN of the length of the transmissiondata, i.e., the number of transmission frames. To this end, the lengthof the transmission frame should have a fixed value. That is, since thewhole length of the data is indicated in the first transmitted frame,this method can be used only for the case where no additional data isgenerated during transmission of data over the CPCH. However, theadditionally generated data, i.e., the data generated after the totalnumber of the frames is determined, should be transmitted in the nextCPCH access process. The UTRAN then analyzes the total number of theframes, provided from the UE over the first frame, and counts the numberof the frames received from the UE. The UTRAN determines whether thenumber of the received frames is equal to the analyzed total number ofthe frames. If the number of the received frames is equal to the totalnumber of the frames, the UTRAN releases the CPCH over which the frameswere received.

FIG. 40 shows a method for effectively releasing the CPCH using acontrol frame according to another embodiment of the present invention.When the control frame is used, it is necessary to distinguish the userdata frames from the control frame indicating the end of data exchangedbetween the UTRAN and the UE. As shown in FIG. 40, 1-bit flags F can beused to distinguish the control frame C from the data frames D.

Referring to 40, the UTRAN can determine whether the next frame is acontrol frame C or a data frame D, depending on a value of the flag F.Here, the control frame can be constructed in a specific pattern. Forexample, the control frame can be constructed in a pattern of 1111 . . ., 0000 . . . , or 101010 . . . . However, since there is a possibilitythat a user data frame having the same structure as the control framewill be generated, the flag bit should be used.

As in the case of FIG. 40 where the control frame is used, it ispossible to construct a transport block in a specific pattern at the MAClayer and use the constructed transport block in releasing the CPCH.Next, a detailed description will be made of a method for releasing theCPCH using the method proposed in FIG. 40.

MAC PDUs (Packet Data Units) are transmitted to the physical layerwithin one TTI (Transmission Time Interval), and these are defined as aTBS (Transport Block Set). The TBS is comprised of one or more transportblocks (TBs), and each TB is comprised of the MAC PDU. The TB registersan amount of data transmitted in one frame in order to increaseutilization efficiency of the CPCH. The TB is sequentially transmittedfrom the RLC (Radio Link Control) and can be multiplexed with a TBgenerated from another logical channel. However, the TBs generated inthe same logical channel are sequentially transmitted from the RLC tothe physical layer.

A UE requiring the CPCH constructs data based on the TBS size, NF_maxand TTI parameters received from the UTRAN. The TBS size parameter isfundamentally determined depending on the data rate. If the TSB sizeparameter is not multiplexed in the MAC layer, it has a transparentproperty in the MAC and RLC layers, and protocol control information(PCI) is not added thereto. As stated above, the TB is the minimum unitof the data transmitted by the UE and constitutes the presentlytransmitted TBS, and CRC is added to the TB so that the UTRAN canperform error check. In the normal CPCH transmission, when there is nodata generated, the TB is not constructed. However, for the rapidrelease of the CPCH, it is necessary to construct the TB. At this point,the TB has length (or size) ‘0’, since there is no user data transmittedby the UE. Upon receipt of the TB having size ‘0’, the UTRAN releasesthe CPCH on judgment that data transmission of the CPCH is ended. TheTBS comprised of one or more TBs may include a plurality of the TBshaving size ‘0’, and the TBS includes a field indicating the number ofthe TBs having size ‘0’.

FIG. 41 shows a structure of a frame comprised of the TBs having size‘0’ used to release the CPCH. As shown in FIG. 41, the zero size TBindicates the end of the CPCH. Since there occurs no TB with size ‘0’during transmission of the CPCH, the flag field shown in FIG. 40 is notrequired which is used to distinguish the control frame from the dataframe.

A method for releasing the CPCH for the TB size=0 shown in FIG. 41 mustbe previously defined in order to release the CPCH between the UTRAN andthe UE. However, if the UTRAN misrecognizes the ‘TB size≠0’ as ‘TBsize=0’ because of a frame transmission error, the UTRAN releases theCPCH. To prevent this, i.e., to increase reliability of releasing theCPCH, it is necessary to transmit ‘TB size=0’ two or more times. Inorder to indicate the number of TBs for the case where ‘TB size=0’ istransmitted two or more times, a field indicating the number of ‘TBsize=0’ is required. However, the number of TBs used to release the CPCHis a parameter which can be determined by the UTRAN. Therefore, theUTRAN is required to inform the UE of the number of ‘TB size=0’ to beused in releasing the CPCH, through an RRC broadcasting message.

In the foregoing description, when the UE has no message to transmitover the assigned CPCH channel, the UE uses the zero-sized transportblock (TB) in order to inform the UTRAN of the corresponding situation.In order for the UE to inform the UTRAN that there is no more data totransmit over the CPCH, the UE defines a specific TFI (Transport FormatIndicator) of PHY_DATA_REQ primitive for enabling the physical layer toindicate the end of the transmission frame so as to transmit thedesignated number of ‘TB size=0’. Upon receipt of the primitive, thephysical layer creates a corresponding EOF field.

In this embodiment, the UE transmits a designated number of EOFs (End ofFrames) received from the UTRAN. This is to enable the UTRAN to be ableto receive the EOF with higher reliability. In this method, the upperlayer of the UE transmits the primitive to the physical layer, so thatthe physical layer can transmit a transmission end signal to the UTRAN.

However, the physical layer may not transmit the transmission end signalto the UTRAN. That is, if the upper layer transmits a primitiveindicating a zero transport format as an indication that there is nomore data to transmit, the physical layer immediately ends thetransmission. Therefore, it is possible to reduce unnecessary uplinkinterference. Accordingly, the UTRAN can perceive that there is nosignal from the UE. Hence, upon failure to receive any signal for apredetermined time, the UTRAN releases the pertinent channel havingdetermined that the UE has ended the transmission. Since the CPCH isreleased, the UTRAN indicates that the released channel is free (or notin use), using the CSICH channel for broadcasting occupancy of therespective PCPCHs. After releasing the channel, the UE can determinewhether the channel is correctly released, by examining whether theUTRAN broadcasts the fact that the channel released by the UE is free.

Meanwhile, if it is determined that the CPCH is free by monitoring theCSICH, the UE can stop data transmission through the CPCH. Such asituation may occur when the UTRAN releases the CPCH channel onmisjudgment that there is no signal to the CPCH or data transmission isended.

Since the UE transmits the designated number of EOFs without consideringthe present radio environment in order to report an end of transmissionto the UTRAN, the UE may increase unnecessary uplink interference.Further, a delay may occur in performing another operation.

Therefore, if the UTRAN determines the maximum number of EOFs and sendsthe corresponding information to the UE, then the UE actively determinesthe number of EOF transmission according to the channel condition andtransmits the EOF by the determined number. Accordingly, it is possibleto reduce the uplink interference by preventing the unnecessaryoperation which may be performed in the UE.

Further, in the 3GPP standard (UMTS standard), by defining EOFtransmission number as the maximum transmittable number, it is possibleto reduce an amount of information to be added to an RRC CPCH SetInformation Message in which the information necessary for the inventionshould be included. Table 9 below shows how the invention adds theinformation to the existing RRC CPCH Set Information Message. In Table9, ‘[ . . . ]’ indicates omission.

TABLE 9 Information Element/ IE type and Group Name Presence Multreference Semantics description CPCH set ID M CPCH set ID Indicates theID number for a particular CPCH set allocated to a cell [ . . . ] [ . .. ] [ . . . ] [ . . . ] [ . . . ] Maximum M Integer Maximum allowedallowed (1 . . . 15) number of EOF Number transmission of EOF [ . . . ][ . . . ]

The UE determines the number of EOF transmission according to the uplinkinterference level, if it is necessary to transmit EOF. Since the uplinkinterference level ranges from −110 dBm to −70 dBm, there exist a totalof 40 uplink interference levels. Further, if the Maximum allowed Numberof EOF broadcasted in the CPCH Set Information Message of Table 9 is Nand Step is min(40/N), the transmission number N_EOF_TX is determined byTable 10 below.

TABLE 10 N_EOF_TX UL Interference Level Range 1 (−70 dBm − (Step * 1-1)~ −70 dBm 2 (−70 dBm − (Step * 2-1)) ~ (−70 dBm − Step * 1) 3 (−70 dBm −(Step * 3-1)) ~ (−70 dBm − Step * 2) . . . . . . N −100

The UE can use TFCI of UL DPCCH to indicate an end of data transmissionover the CPCH. If the TFCI is used, the physical layer of the Node B caninform the Node-B RCC of EOT (End of Transmission) of the CPCH in a unitof 10 ms radio frame, thereby making it possible to rapidly release theCPCH.

To this end, the UTRAN must be signaled such that a specific TFI(Transport Format Indicator) should be mapped to EOT in the TFS(Transport Format Set) of the CPCH Set Information in the broadcastingmessage.

In addition, it is necessary to indicate how many times the EOT radioframe should be transmitted, using the RRC message. For the RRC message,Table 11 below can be used. Hence, the UE transmits the radio frames bythe indicated number. However, if Table 10 is used, the UE can transmitthe EOT radio frames according to the uplink radio interference level.

If the number of EOFs determined by the UE is smaller than the maximumnumber of EOFs transmitted to the UE by the UTRAN, the EOFs aretransmitted by the number determined by the UE. However, if the maximumnumber of the EOFs transmitted by the UTRAN is smaller than the numberof EOFs determined by the UE, the EOFs are transmitted by the maximumnumber of EOFs transmitted by the UTRAN.

Alternatively, the UE can determine the number of EOFs and transmit thedetermined number to the UTRAN in a state where only the EOF format isappointed with the UTRAN.

A detailed transmission scheme of the FIG. 41 is shown in FIG. 42. TheUTRAN analyzes the TFCI transmitted over the DPDCH and determineswhether the frame transmitted over the DPDCH has TB with size ‘0’. TheUTRAN transmits the received data to a proper transmission channel byanalyzing information about the method (i.e., decoding anddemultiplexing) for processing the presently received data by analyzingthe TFCI. When the UE has no more data to transmit, the MAC layertransmits the TFCI to the physical layer so as to construct the TB withsize ‘0’. Upon receipt of such information, the physical layerconstructs information indicating that TB with size ‘0’ is included inthe TFCI.

Through this process, the UTRAN perceives that TB has size 0, based onthe information for decoding the received data. Therefore, the UTRAN caneffectively release the CPCH.

As shown in FIG. 42, EOF proposed in the invention is a specific framehaving TB with size ‘0’, and the EOF is transmitted to the UTRAN torapidly release the CPCH when the UE has no data to transmit before theexpiration of NF_MAX, thereby contributing to effective scheduling ofthe uplink common channel.

In FIGS. 41 and 42, it is necessary to add IE of the RRC message shownin Table 11 below.

TABLE 11 Information Element/ IE type and Group Name Presence Multreference Semantics description CPCH set ID M CPCH set ID Indicates theID number for a particular CPCH set allocated to a cell [ . . . ] [ . .. ] [ . . . ] [ . . . ] [ . . . ] Number M Enumerated Number of framesto of EOF (1,2,3,4,5) indicate end of CPCH transmission [ . . . ] [ . .. ]

As another method, it is possible to release the CPCH channel byinserting a specific pattern known to both the UTRAN and UE in aspecific field of the physical layer. For the release of the CPCHchannel, the UE must inform the UTRAN of an end of frame transmission,so that the UE can use a specific field of the uplink frame physicallayer. The existing uplink frame physical layer includes a TPC(Transport Power Control) field, a PILOT field, a TFCI (Transport FormatCombination Indicator, or a data rate information) field, and a FBI(Feed Back Information) field. These fields can be individually used torelease the CPCH channel. That is, after completing transmission of theCPCH frame, the UE transmits one or more release frames by inserting aspecific pattern in the TPC field, the PILOT field, the TFCI field, orthe FBI field.

A description will now be made of an exemplary method for informing theUTRAN that the UE has transmitted the last frame, using the TFCI fieldas the specific pattern. If each physical layer frame is comprised of 15slots and a length of the TFCI field per slot is N bits, one frameincludes 15×N TFCI bits. In this case, the “specific pattern” refers tothe TFCI pattern with length 15×N. The UE divides the specific patternof length 15×N, appointed with the UTRAN, by N bits, and transmits thedivided patterns by inserting them in the TFCI field of each slot. Uponreceipt of each frame, the UTRAN determines whether the received bits inthe TFCI field in the received frame are equal to the pattern appointedwith the UE, and if so, judges that the CPCH transmission is ended. Inthis exemplary method, the UTRAN makes the judgment in a unit of oneframe. Alternatively, the UTRAN may make the judgment in a unit oflength longer or shorter than one frame. That is, if the UTRAN makes thejudgment in the unit of M slots (M<15 or M>15), a length of theappointed pattern becomes N×M.

A description will be made of another exemplary method for informing theUTRAN that the UE has transmitted the last frame, using the PILOT fieldof the DPCCH as the specific pattern. As in the TFCI field, the PILOTfield indicating the end of frame (EOF) also becomes a pilot pattern oflength 15×N by defining the N-bit pilot pattern and including the N-bitpilot pattern in the 15 slots of the physical layer frame. The UEdivides the specific pattern of length 15×N, appointed with the UTRAN,by N bits, and transmits the divided patterns by inserting them in thePILOT field of each slot. Upon receipt of each frame, the UTRANdetermines whether the received bits in the PILOT field in the receivedframe are equal to the pattern appointed with the UE, and if so,determines that the CPCH transmission is ended. In this exemplarymethod, the UTRAN makes the determination in a unit of one frame.However, the UTRAN may make the determination in a unit of length longeror shorter than one frame. That is, if the UTRAN makes the determinationin the unit of M slots (M<15 or M>15), a length of the appointed patternbecomes N×M.

A description will be made of further another exemplary method forinforming the UTRAN that the UE has transmitted the last frame, usingthe specific pattern. In this method, the UE can continuously transmit aDOWN command as the TPC value for a predetermined period. If the TPCvalue is DOWN for the predetermined period, the UTRAN withdraws the CPCHresource. As yet another example, when the pilot bit pattern is used forthe specific pattern, the UE phase-inverts the existing pilot bit andtransmits the inverted pilot bit to the UTRAN.

As mentioned above, the appointed pattern can be transmitted either tothe TFCI field or to the TPC, PILOT and FBI fields.

Upon receipt of one or more frames having the appointed pattern in thefield appointed with the UE, the UTRAN recognizes the end of CPCHtransmission and releases the CPCH resource. In addition, the specificpattern can be constructed by combining one or more fields, and thispattern must be known to both the UTRAN and the UE. As an example ofconstructing the specific pattern by combining one or more fields, thespecific pattern can be constructed by combining the TFCI field and theFBI field, as follows. If the physical layer frame is comprised of 15slots and a length of the TFCI field per slot is NTFCI and a length ofthe FBI field per slot is NFBI, then a length of the pattern per framebecomes (NTFCI+NFBI)×N bits. After transmitting every CPCH frame, the UEsequentially inserts the pattern appointed with the UTRAN in the TFCIfield and the FBI field before transmission. The UTRAN receives the TFCIfield and the FBI field for a one-frame interval and determines whetherthe received fields are equal to the pattern appointed with the UE. Ifthe received fields are equal to the appointed pattern, the UTRANreleases the CPCH resource. Even in this case, the pattern length can bevaried according to the unit in which the UTRAN can make the judgment.Any combination of TFCI, PILOT, TPC and FBI is available fortransmission of the appointed pattern. The number of fields combined toconstruct the specific field may be higher than 2.

FIG. 43 shows a novel process for releasing the CPCH in comparison withthe conventional process for releasing the CPCH. It is noted from FIG.43 that the novel CPCH releasing process performs the CPCH releaseoperation at least one frame faster than the conventional process, thuscontributing to effective scheduling of the uplink common channel.However, in order to determine whether the received frame is an errorframe or a normal frame indicating the end of data transmission, theUTRAN must monitor many frames, so that the actual CPCH releasingprocess will be delayed.

As described above, the UTRAN actively allocates the CPCH requested bythe UE and can reduce the time required for setting up the CPCH. Inaddition, it is possible to decrease a probability of a collision whichmay be caused when a plurality of UEs requests the CPCH, and to preventa waste of radio resources. Furthermore, it is possible to secure stableallocation of the common packet channel through the PC_P between the UEand the UTRAN, and to provide stability in using the common packetchannel.

In addition, the UTRAN can effectively release the CPCH by schedulingthe CPCH according to a length of the transmission data, thus making itpossible to secure effective use of the CPCH and provide the packetservice to the increased number of subscribers.

While the invention has been shown and described with reference to acertain preferred embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

1. A method for indicating by a first user equipment (UE) an end of astream of data frames so as to transmit data to be transmitted byanother UE after the end of a stream of the data frames in a mobilecommunication system, which includes a stream of data frames withtransmission data, and a stream of control frames wherein, each of thecontrol frame having TFCI (Transport Format Combination Indicator) fieldindicating a length of corresponding data frame, the method comprisingthe steps of; spreading the stream of control frames with a firstorthogonal variable spreading factor (OVSF) code and the stream of dataframes with a second orthogonal variable spreading factor (OVSF) code;transmitting the spread data in the data frames over an uplink commonchannel and the spread control data in the control frames over an uplinkcontrol channel from the first UE to a UTRAN (UMTS (Universal MobileTelecommunications System) Terrestrial Radio Access Network); and upontransmission of the last one of the data frames, generating a specificcontrol frame to represent end of data transmission by configuring aTFCI bits indicating the data frame block size being zero; andrepeatedly transmitting the specific control frame to UTRAN over theuplink control channel.
 2. The method as claimed in claim 1, wherein agiven number is designated by the UTRAN through a broadcasting channelso as to the first UE repeatedly transmits the specific control frame bythe designated given number.
 3. The method as claimed in claim 1,wherein the first UE determines how many times repeatedly transmittingthe specific control frame according to a present communication channelcondition.
 4. A method for indicating by a first user equipment (UE) anend of transmitting data frames so as to enable a UTRAN (UMTS (UniversalMobile Telecommunications System) Terrestrial Radio Access Network) toassign a common packet channel to another UE in a mobile communicationsystem, the UE transmitting plurality of data frames having data to betransmitted over a common packet channel with associated control frames,each of the control frame having pilot symbols, TPC (Transmission PowerControl) and TFCI (Transport Format Combination Indicator) bitsindicating length information of data included in each of thecorresponding data frame, the method comprising the steps of: monitoringwhether the transmission data is completely transmitted through the dataframes; upon monitoring an end of data transmission, constructing aspecific control frame with the TFCI bits indicating that no data isincluded in the data frame in order to represent end of datatransmission; and transmitting the constructed frame over the commonpacket channel.
 5. The method as claimed in claim 4, wherein the firstUE transmits the control frame representing the end of data transmissionfor a given number designated by the UTRAN through a broadcastingchannel.
 6. The method as claimed in claim 4, wherein the first UEdetermines a transmission number to transmit the control framerepresenting the end of data transmission according to a present channelcondition.
 7. A method for indicating by a first user equipment (UE) anend of transmitting data frames in order to enable a UTRAN (UMTS(Universal Mobile Telecommunications System) Terrestrial Radio AccessNetwork) to assign a common packet channel to another UE in a CDMA (CodeDivision Multiple Access) mobile communication system, the methodcomprising the steps of: requesting assignment of a common packetchannel assignable in the UTRAN; receiving a channel assignment preamblesignature indicating a common packet channel by the UTRAN in response tothe request; transmitting by the first UE, at least one start oftransmission frame to the UTRAN; sequentially transmitting the dataframes over the assigned common packet channel and their associatedcontrol frames over a control channel associated with the common packetchannel; and transmitting at least one specific control frame, in anappointed field of which a given bit pattern appointed with the UTRAN isregistered, in order to inform the UTRAN of an end of data transmissionupon completing data transmission.
 8. The method as claimed in claim 7,wherein the appointed field is a TFCI (Transport Format CombinationIndicator) field of the associated control frame.
 9. The method asclaimed in claim 7, wherein the appointed field is a pilot filed of theassociated control frame.
 10. The method as claimed in claim 7, whereinthe appointed field is a feed back information (FBI) field.
 11. Themethod as claimed in claim 7, wherein the appointed field is a transportpower control (TPC) field.
 12. The method as claimed in claim 7, whereinthe appointed field includes at least two of TFCI, pilot, FBI and TPCfields.
 13. A method for indicating by a first user equipment (UE) anend of transmission in order to enable a UTRAN (UMTS (Universal MobileTelecommunications System) Terrestrial Radio Access Network) to permit aphysical common packet channel to another UE in a CDMA (Code DivisionMultiple Access) mobile communication system, the method comprising thesteps of: receiving, by the first UE, a channel status indicatingchannel signal indicating availability of each physical common packetchannels from the UTRAN; requesting, by the first UE, permission ofusage for a common packet channel to the UTRAN; receiving, by the firstUE, a signal indicating permission of usage for the physical commonpacket channel from the UTRAN; examining, by the first UE, whether thepresently permitted physical common packet channel status is changed tonon-available status by receiving a channel status indicating channelsignal after the requesting step; determining whether to transmit thedata frames over the permitted physical common packet channel, based onthe examination result; sequentially transmitting data frames having apacket data to transmit over the permitted physical common packetchannel to the UTRAN when the permitted common packet channel status ischanged to non-available status; and transmitting an end of transmissionframe indicating the data frame is completely transmitted over thephysical common packet channel.
 14. A method for indicating by a firstuser equipment (UE) an end of frame transmission in order to enable aUTRAN (UMTS (Universal Mobile Telecommunication System) TerrestrialRadio Access Network) to assign a common packet channel to another UE ina CDMA mobile communication system, the method comprising the steps of:requesting, by the first UE, assignment of a common packet channelassignable in the UTRAN; assigning, by the UTRAN, a common packetchannel in response to the request; sequentially transmitting, by theUE, data frames over the common packet channel assigned by the UTRAN,and ending the data frame transmission upon completing the transmission;releasing, by the UTRAN, the common packet channel upon failure toreceive a frame for a predetermined time, and broadcasting presentlyassignable common packet channels including the released common packetchannel over a broadcasting channel; and examining, by the UE, whetherthe presently assignable common packet channels, broadcast by the UTRANthrough the broadcasting channel includes the assigned common packetchannel, and determining whether to release the assigned common packetchannel, based on the examination.
 15. The method as claimed in claim14, further comprising the step of ending, by the UE, transmission ofthe data frames if it is examined that the assigned common packetchannel is released during the sequential transmission of the framesover the common packet channel assigned by the UTRAN.
 16. A method forindicating by a first user equipment (UE) an end of a stream of dataframes so as to transmit data to be transmitted by another UE after theend of a stream of the data frames in a mobile communication system,which includes a stream of data frames with transmission data, and astream of control frames wherein, each of the control frame having TFI(Transport Format Indicator) field indicating transport block size ofthe data frame, the method comprising the steps of; spreading the streamof control frames with a first orthogonal variable spreading factor(OVSF) code and the stream of data frames with a second orthogonalvariable spreading factor (OVSF) code; transmitting the spread data inthe data frames over an uplink common channel and the spread controldata in the control frames over an uplink control channel from the firstUE to a UTRAN (UMTS (Universal Mobile Telecommunications System)Terrestrial Radio Access Network); upon transmission of the last one ofthe data frames, generating a specific control frame to represent end ofdata transmission by configuring a TFI bits indicating a zero sizedtransport block; and transmitting the specific control frame to UTRANover the uplink control channel.
 17. The method as claimed in claim 16,further comprising the step of repeatedly transmitting the specificcontrol frame as many as a given number of times.
 18. The method asclaimed in claim 17, wherein the given number is designated by the UTRANthrough a broadcasting channel so as to the first UE repeatedlytransmits the specific control frame by the designated given number. 19.The method as claimed in claim 17, wherein the first UE determines howmany times repeatedly transmitting the specific control frame accordingto a present communication channel condition.
 20. A method forindicating by a first user equipment (UE) an end of transmitting dataframes so as to enable a UTRAN (UMTS (Universal MobileTelecommunications System) Terrestrial Radio Access Network) to assign acommon packet channel to another UE in a mobile communication system,the UE transmitting plurality of data frames having data to betransmitted over a common packet channel with associated control frames,each of the control frame having pilot symbols, TPC (Transmission PowerControl) and TFI (Transport Format Indicator) bits indicating transportblock size of the data frame, the method comprising the steps of:monitoring whether the transmission data is completely transmittedthrough the data frames; upon monitoring an end of data transmission,constructing a specific control frame with the TFI bits indicating azero sized transport block in order to represent end of datatransmission; and transmitting the constructed frame over the commonpacket channel.
 21. The method as claimed in claim 20, wherein the firstUE transmits the control frame representing the end of data transmissionfor a given number designated by the UTRAN through a broadcastingchannel.
 22. The method as claimed in claim 20, wherein the first UEdetermines a transmission number to transmit the control framerepresenting the end of data transmission according to a present channelcondition.